Chemistry Thursday: Ionic bonding and salts!

Atoms are the building blocks of all molecules, so we need to know a little about them to understand how molecules work. An atom is happiest when it has eight electrons on its outer shell. (This is called the octet rule and it applies to the elements we'll get to know the best - those under number 20 - up to calcium.) If an atom has less than eight, it gets seriously desperate and it goes on a mighty quest for another electron!

This is one of the reasons the noble gases are so stand-offish. Neon, argon, helium - they have 8 electrons in their outer shells, so they have no need to interact with those common elements to get electrons. They're the haves of the periodic table! 

Let's say you're sodium and you have an extra electron (the + on the element listing). You really want eight electrons, so you go out on the town hoping to attract another atom who needs another electron or has seven to share. Hey, chlorine! You're looking mighty attractive with those seven extra electrons. Can I buy you a drink? And before you can say I could have had a V8, we have sodium chloride (NaCl).

Generally, when you see something like that + (with or without numbers) in the right hand corner for sodium, that means we have an extra electron, or two, or three. Generally, when you see a minus sign (-, with or without numbers), this means that we are missing electron(s) in the outer shell. 

The general process is this...The outer orbital of one of the atoms has a vacancy - in this case, chlorine - which means it can collect an electron and complete that octet. The nucleus of the chlorine offers the sodium a tighter bond, so the sodium gives up its electron. Ionic bonding relies on electrostatic attraction between the atoms to work.

Electrostatic attraction: "Electrostatic attraction is the attraction that an atom has for electrons." Now, I realize we're going in circles here, but this is the best definition I could find that doesn't require my brain to hurt too much this early in the morning. So the sentence above could be re-written as, "Ionic bonding relies upon the attraction that an atom has for electrons to work". Sounds good to me!

This process is called ionic bonding. It generally only happens between a cation (positively charged atom, usually a metal from the right hand side of the table) and an anion (negatively charged ion, usually a non-metal from the left hand side of the table).

Click on the link to see some cute animations of various atoms coming together in ionic bonding!

When sodium and chloride come together we get a salt. (Definition: Salts are ionic compounds composed of a positively charged or cationic ion and a negatively charged or anionic ion. They are electrically neutral. The positively charged ion is a metal, like sodium or calcium, and the negatively charged ion is a non-metal, like chlorine or sulfur.) We can get other salts, too. Magnesium sulfate (or Epsom salts), sodium sulfate (Glauber's salts), copper (II) sulfate - the one to your left, so pretty!) and so on - there are so many salts out there and so many ways to create them! I bet you didn't think salt could be fun, but it is!

Join me next week for covalent bonding!

Point of interest! There's a new list on the blog called chemistry links! I'll be putting these posts on that page in the proper order so you can refer back to it, and you'll find links to any chemistry related posts on the blog in that section!

I love this interactive periodic table! Bookmark it and use it! It's great (and some of it is lime green!) 

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Questions I missed: Solubility of our powdered ingredients

In this post, Lalla writes: If the solubility is 0.5% at 25°C, does it mean if we dissolve a higher concentration at say 35°C the allantoin will crystallize as it cools down? If I try to dissolve MSM and allantoin and caffeine in water, will their respective solubility decrease because of the other ingredients?

Solubility is generally measured at STP, which is standard temperature and pressure. The official IUPAC STP is 0˚C and 100 kPa (the pressure at sea level. We generally use SATP or standard ambient temperature and pressure, which is considered to be 25˚C or 77˚F and 100 kPa (sea level).

If something has a solubility of 0.5% at SATP, this means at 25˚C you can dissolve 0.5 grams of it in 100 grams of solvent (alcohol, water, oil, and so on). So let's say you have something like green tea extract and its solubility is 0.5% at SATP, this means that I should be able to dissolve 0.5 grams of green tea extract in 100 grams of water at 25˚C. If it cools down below 25˚C, the solubility might go down slightly, but not enough that we have to worry about it!

When we increase the temperature, we generally increase the solubility of the ingredient, so we can dissolve more of it. I can get far too much powdered extract to dissolve in my toner when it's warm (45˚C or slightly lower), but it'll precipitate when it cools down (see the picture above). Which is why we want to make sure we always stay at the suggested usage rates!

One exception to this increase the temperature, increase the solubility is carbon dioxide in pop. When we cool it down, it gets more soluble, which is why a pop from the fridge feels fizzier than that from your shelf! Interesting, eh?

But the question Lalla asked is about how solutes affect other solutes. If you have something like allantoin (used at 0.5%) and you add a powder like MSM (up to 5%) and another powder like caffeine (not sure of percentage), what happens if you put them all together? In theory, water can only hold so much and you will reach a point when you can't put anything more into that water. It's not about the chemistry of the other ingredients - as long as allantoin and MSM don't combine to great nitroglycerin or something like that - but about how much the solvent can hold.

If you're making something like a toner, you'd be surprised at how much you can add before you get a precipitate! Water is a great solvent for things that like to be dissolved in water, and you could get quite a bit in there. I've made toners that contained a ton of things - 0.5% allantoin, 0.5% green tea extract, 0.5% chamomile extract, 0.5% grapeseed extract, 2% niacinamide, 2% MSM, 2% salicylic acid (what's that - 8% powder?) and they stayed nice and solubilized, and the product stayed liquid!

I will point out that this one looks kinda muddy, and it isn't going to be clear at any point in its lifetime because I've loaded it up with tons of great extracts and powders. But the question was whether the various powders would have an effect on the solubility of other powders, and the answer in general is no, they shouldn't if we're using things at suggested rates!

Here's a toner filled with tons of water soluble powders, and here's another!

Did I answer your question? Join me tomorrow for more fun with cosmetic chemistry!

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Chemistry Thursday: The atom!

The periodic table. You see it everywhere, but what the heck does it all mean? Take a look at it for a moment. It's arranged by atomic number, which is the number of protons in an atom's nucleus. Let's meet the atom!

When we look at the periodic table of elements, we're looking at the organization of atoms - carbon, oxygen, helium, uranium and so on. There are three parts of an atom. The proton, the neutron, and the electron.

The proton is found in the nucleus of the atom and is positively charged. Every element has a different number of protons. If it has 1 proton, it's hydrogen. Two protons and you've got helium. Six protons gives us carbon and 16 gives us sulphur. Change the number of protons, you change the element. We have the same number of protons as we do electrons, which leads to a neutrally charged atom.

The neutron is found in the nucleus of the atom and is neutrally charged. Change the number of neutrons, and you have an isotope! Normal, everyday carbon-12 has 6 protons and 6 neutrons - carbon-14 has 6 protons and 8 neutrons, giving us a radioactive isotope. (That's why they use it in carbon dating! It decays at a predictable rate, so we can measure the decay and figure out the age of something!) Carbon will always have 6 protons - that's what makes it carbon - but the number of neutrons can change slightly (in carbon it might be 8, it's never going to be 42!). When you hear about elements like uranium-238 or uranium-235, we're talking about isotopes, which are elements that have the same number of protons but different neutrons.

The electron is found swirling around the nucleus. It's really tiny compared to the proton and neutron, and it carries a negative charge. In a neutral state, an atom will have the same number of electrons as it does proton. There's a ton of interesting stuff out there on locating the electrons on an atom - uncertainty principles and all of that, but for now we're going to go with the basic idea that electrons are found outside the nucleus of an atom on things called orbitals.

Orbitals are represented in this picture by those blue lines, the electrons by the red dots!

When you read the periodic table, look at each element to decode its meaning! This is sodium from the first group or column on the periodic table. It is number 11, which means it has 11 protons and 11 electrons (because they are the same number). It weighs 23.0 grams per mole (which is 6.02 x 10(23) atoms in 23 grams of sodium) and it has that plus sign in the corner. This means that there is one electron swirling around on its outer orbital. (This will become relevant in time.)

If you like the periodic table as much as I do, download this periodic table and play periodic table Scrabble! I can't spell my name (Susan - Sulphur-uranium-sulphur-there's no A on its own!) but I can spell my best friend's husband's name - Cameron (Carbon-Americum-Erbium-Oxygen-Nitrogen) and genius (Germanium-Nitrogen-Iodine-Uranium-Sulphur). My last name is easy to create - it's just Ni2! This is a great way to learn where the elements are on the table and their abbreviations!

Join me later this week for a little more chemistry fun!

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Question: Do you want to know more basic chemistry?

What do you think about having a post in which a basic concept in chemistry is explained every week? We could go over basic concepts in chemistry or I could answer questions or whatever you want. I'm thinking about things I've already covered like anionic, cationic, and non-ionic, solubility, miscibility, emulsification, and so on, but including things like redox reactions, acid-base reactiosn, and the like.

I realize I'm a science geek and I find these things interesting, but it is possible that you don't. Hence the question! Be honest! 

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Thickener: Behenyl alcohol

I do love working with thickeners in my products! We know that cetyl alcohol can produce something slicker and silkier than stearic acid, and that cetearyl alcohol can offer those same qualities with a little more waxiness, so what does behenyl alcohol bring to the party? First, a review....

Cetyl alcohol is a fatty alcohol that contains 16 carbons on a long chain. Because it's saturated, it will have a long shelf life, at least two years! It has a required HLB of 15.5. We add it to our lotions to thicken the product and give it some extra glide. It has a melting point of about 49˚C.

Cetearyl alcohol (also known as cetostearyl alcohol and cetylstearyl alcohol) is a blend of cetyl and stearyl alcohols that we can use at up to 25% in our creations. It can be a 30% to 70% cetyl alcohol to stearyl alcohol or 30% to 70% stearyl alcohol to cetyl alcohol, but you might find 50-50 from some manufacturers. (I have no idea which version I have, but it looks a lot like Lanette O, which is 50-50.) It has an HLB of 15.5 and is used as a thickener. Its melting point is 49˚C to 58˚C. It's also saturated, so it will have a long shelf life.

Both cetyl alcohol and cetearyl alcohol are oil soluble, meaning they would go in the heated oil phase of our products, and they will thicken our lotions, creams, body butters, and other emulsified products when we use them in this way. Fatty alcohols are great in our conditioners because they boost the substantivity of the cationic ingredient, meaning you get more conditioning without having to add more conditioner!

Behenyl alcohol is a chain of 22 carbons with a melting point of 65˚C to 73˚C (as we increase the number of carbons, we see an increase in the melting and boiling points of our fatty alcohols). It is also saturated, and has an HLB of 15.5. It is also oil soluble, so it should be used in the heated oil phase of our products. It will boost the substantivity of our conditioners.

How am I going to use this ingredient? I'm going to try it out in my duplication of the Body Shop's Hemp Hand Protector in place of the cetearyl alcohol. So join me tomorrow for that recipe and my results!

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Question: Evaporation!

Tara made a great comment in response to yesterday's question about why some of my lotion recipes are so thick - I used to agree that your recipes came out awfully thick, but then I learned to account for evaporated water. I now make sure my vessels that contain my ingredients for heating weigh the same before AND after heating. I make up the difference with distilled water that has been heated and held.

If you're not compensating for water amount, you will get a thicker lotion than you expected! Let's say you need a grand total of 70% water in your lotion. If you heat and hold for 20 minutes, you might end up with a total of 60% water in your your lotion and that's going to make for a much thicker lotion! So make sure you measure your water phase with container at the start of the heating and holding process and the end, and add enough heated water to get back to the number you need in the recipe.

And this relates to this question from Always Looking 4 1 More (from this post): I love formulating but I've been trying to keep my formulating (and my life) as healthy as possible. So I'm wondering how much of the "good stuff" that we use many natural oils, aloes, etc. for is retained in it after we heat & hold for 20 mins. or so? It seems the "good stuff" will all be destroyed and all we have left is a product that just "feels good and smells delightful". Are we inadvertently sending nutrients out into the air while trying to kill different kinds of germs and germ-causing elements in the oils and waters (eg, aloe)?

We've addressed the question of possible goodness loss in oils in this post, but let's summarize that before moving on to the water soluble ingredients Most oils have a smoke point well over 100˚C (for instance, grapeseed oil is around 216˚C and camellia seed oil is around 485˚F!), and we're heating our products up to 70˚C/158˚F and holding them, so the oils will be just fine. Yes, we might speed up rancidity slightly, though not by much. We aren't ruining any polyphenols or phytosterols or lovely fatty acids or hurting the oil in any way. On the other hand, not heating and holding our oils can have a huge impact on the emulsification of the product, and a failed lotion is definitely something that can ruin our oils and waste our money!

As for the water phase, the only things we add to the heated phases are things that can stand the heat! Anything that can't stand the heat goes into the cool down phase, which is at 45˚C or 113˚F. We aren't boiling our ingredients, and any evaporation we experience will be from the water portion of the lovely ingredient (every liquid ingredient has some water in it!). We are ending up with a more concentrated of the ingredient (for instance, aloe or a hydrosol), which isn't a bad thing. (Although we should add the water back to the product, so it'll all even out in the end.)

If you're really worried about things going out into the air - although I can't think of anything other than water and some smells - you can put a lid on your container, but just watch it to ensure that your ingredients stay around 70˚C or 158˚F. (Don't put the lid or plastic wrap on tightly!) This will also reduce the amount of evaporation in the product.

The good stuff we want from our ingredients include vitamins, minerals, fatty acids, phytosterols, polyphenols, polysaccharides, and more, and those things are either heat tolerable or not. Something like panthenol wants to be added at the cool down phase because it can't tolerate heat, whereas aloe vera can.

If you're in doubt as to whether your ingredient can stand the heat, click here for some ideas on when to add our products to the various phases! And here are two posts on evaporation - surface area and evaporation and compensation for evaporation when making products!

And keep the questions and comments coming by commenting on a post or writing to me, Swift, at sjbarclay@telus.net! I'll do my best to get to your question in the coming days!

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Two new elements!

Two new elements have been added to the periodic table at 114 and 116, and they are - as yet - unnamed! I would like to suggest that one of them have the symbol E as it would make Periodic Table Scrabble much more fun (right now, we only have Er as an option) so I'm suggesting Embiggenium for one of them. And we don't have an A on its own (which means I can't spell Susan - Sulphur, uranium, sulphur...nothing!), so what about Awesomium? For the other one, I'm thinking Blondiedogium has an adorable ring to it or perhaps Frinkium (glavin!)

As an aside, I do think some of the comments below the story are sad and alarming. Like this one, "I'd call them ivory-tower-elitism to reflect that ordinary, hockey-watching, Tim Hortons Canadians don't really care." You're wrong! We do care! Idiot...

If you get a chance, I really encourage you to download the podcast for The Infinite Monkey Cage (Stephen Fry is on this week!!!). The fact that this radio show appears on a Monday afternoon in the UK shows me that people are interested in science!

If you had all the power, what would you call the new elements?

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Happy birthday, currently reigning monarch of the Commonwealth!

Happy Victoria Day! It's a statutory holiday in B.C. (remember, we're still part of the Commonwealth!) and I'm off work. Today celebrates the birthday of the reigning Canadian monarch (scheduled for the Monday on or before May 24, which was Queen Victoria's birthday). So I'm off work today and planning to slob around the house enjoying a little rest and relaxation! (Actually, I think I'll be in the workshop trying to organize, but there'll be some vegging at some point!) 

I love this Mitchell & Webb sketch about Queen Victoria. If you are easily offended, I don't suggest clicking on the link. If you aren't, it's worth it. (If you're a fan of John Cleese's ranting - a la the Parrot sketch - you really must watch David Mitchell's angry logic!)

So I'll see you tomorrow with more fun formulating various things!

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HLB system: An introduction

The next few days are going to be a blast from the past as we learn more about the HLB system. I've updated these posts with more information and ideas so it's not just a re-posting of something I wrote two years ago! 

When we're working with emulsification systems like e-wax or BTMS, we don't really think of how it's going to emulsify our product. We just add the required amount and poof! - we have lotion. If we want to create an emulsification system of our own, we need to turn to the HLB system for guidance! (Please click to see LabRat's amazing PDF on this topic, replete with all the HLB values for oil phase ingredients and emulsifiers! Download this and treasure it!)

For more information on how emulsification works, click here. 

The hydrophilic-lipophilic balance system (or HLB) was created by William Griffin the 1940s as a way of figuring out which emulsifier would work best with the oil phase of an emulsified product. All emulsifiers have a hydrophilic head (water loving) that is generally composed of a water soluble functional group and a lipophilic tail (oil loving) generally composed of a fatty acid or fatty alcohol.

The theory behind HLB is that emulsifiers showing greater solubility in water would be better for oil in water emulsifications; emulsifiers showing great solubility in oil would be better for water in oil emulsifications. The lower HLB valued emulsifiers are better in water in oil as they are more lipophilic; the higher valued HLB emulsifiers are more hydrophilic.

The solubility of a molecule means it will dissolve in the solvent and becomes part of a homogeneous solution. It generally increases with temperature, hence the reason for heating and holding our lotion ingredients. And most emulsifiers we use are in a pellet or flake form, so heating is the only way to incorporate it into a liquid environment.

The HLB value of an emulsifier is determined by the hydrophilic portion of the surfactant. The equation is as follows - HLB = % hydrophilic portion by weight of the molecule divided by 5. (We don't need to know this to use the HLB system, but I'm the kind of girl who has to know everything, so I thought I'd include it for like minded people!) So the higher the number, the higher the portion of the molecule is hydrophilic, and the more water soluble it will be. The lower the number, the less water soluble and more fat soluble it will be. 

Take a look at this polysorbate 80 molecule (HLB 15). Based on this number, we should expect this is to be an emulsifier that would be better suited for oil in water emulsifications because it has such a high HLB number. (And from experience, we know polysorbate 80 is well suited for adding oil to watery things like toners or facial cleansers - not a lot of oil, but enough that we want it not to float on top of the product!) We don't see any fatty acids or alcohols on this chain, so it's going to be a hydrophilic emulsifier with a high HLB value.

Other high HLB emulsifiers include ceteareth-20 (HLB 15.2), Oleth-10 (HLB 12.4), and polysorbate 20 (HLB 16.7).

Glycol stearate has an HLB of 2.9, which means it is a lipophilic emulsifier that would be better suited for water in oil emulsifications due to its low HLB number. Sorbitan stearate (HLB 4.7), glycol distearate (HLB 1.0), and glyceryl stearate (HLB 5.8) are all examples of low HLB emulsifiers.

So how do we use the HLB system to create an emulsifier? We work out the math (I heard some of you shriek there, but if you can remember your elementary school math for figuring out percentages, you'll be fine!) by figuring out the required HLB of our oil phase and the HLB values of our emulsifiers to get a number that matches. (That's for tomorrow's post!)

You will never use one emulsifier alone for a lotion - you might for bubble baths and body washes (glycol distearate to pearlize them), perfumes or toners (polysorbate 20 or 80 to disperse the oils), and so on, but for a lotion, we require a complete emulsification system!

We want to combine a low HLB emulsifier (the one that loves oil more) and a high HLB emulsifier (one that loves water more) at a level that will match the HLB of our oil phase. And we'll want to add enough of these emulsifiers to ensure we get proper, stable emulsification of our product. (I've seen it suggested that you start at 2% and at 4% emulsifiers in your lotions. I'm going to suggest 4% for now to ensure we have enough in the lotion to be successful.)

Please note, there is no hard and fast rule for how much HLB emulsifier to start off with in a recipe. LabRat used to suggest 2% but I like to use 4% or 5%. This is not like Polawax - there is no suggested rate, it's all about trial and error. You will see different amounts of emulsifier used in different recipes. If you're going to use the HLB system, be prepared to work on the calculations for each recipe and the possibility that you haven't used enough emulsifier. This is why I suggest 4% or 5%. 

Join me tomorrow for more fun with the HLB system with a demonstration of how it works (or you can read ahead to this older post if you can't wait, but there will be more added tomorrow!) 

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Chemistry: Peptides

Many of our cosmeceuticals boast the inclusion of peptides, but what the heck are these things? Peptides "are short polymers of amino acids linked by peptide bonds" (from Wikipedia, picture to the left). Polypeptides are "single linear chain of amino acids bonded together by peptide bonds", and are generally no more than 50 amino acids in length, although some would draw the line at 20 amino acids. A polymer is "a large molecule (macromolecule) composed of repeating structural units. These subunits are typically connected by covalent chemical bonds."

Okay, let's break this down a little further. Amino acids are organic molecules that contain an amine group (the nitrogen) and a carboxylic acid group (the carbon with the double bonds to oxygen) and a side chain (the R in the picture). Amino acids are critical to all forms of life as they are the building blocks for proteins and peptides.

A peptide bond is the covalent chemical bond (where the atoms share their electrons) between molecules when the carboxyl group of one molecule reacts with the amine group of the other, producing water in a condensation reaction.

A protein is a biochemical compound with one or more polypeptides. Proteins and polypeptides both contain peptide bonds, but polypeptides tend to be a nice linear chain of molecules while proteins are huge messes of folded molecules that can be massive!

In bath & body products we see proteins, amino acids, and polypeptides as active ingredients all the time, and I'm writing this post as a precursor to a few posts on various peptide and polypeptide cosmeceuticals. So a peptide is a short chain of amino acids linked together by peptide bonds. The shortest one is a dipeptide with two repeating units, then we get a tripeptide, tetrapeptide, and so on - these are called polypeptides (poly meaning "more than one", which means by definition all of the peptides we see in our cosmeceuticals are polypeptides as they have at least two portions held together by the peptide bond). A protein consists of one or more polypeptides and tend to be quite messy.

Peptides tend to do well in acidic pH environments, which isn't an issue because how many of our products are alkaline? Everything we make - except CP soap - should have a pH of 7.0 (neutral) or lower anyway, so that works for us!

A lot of the peptides we use are found in our bodies and have very specific functions in a living creature, and a lot of them are not able to penetrate our skin in a way that is beneficial. Most of the polypeptides are modified to be more available for our skin, and you might see that your peptides are listed as being hydrolyzed or processed or enzymatically digested to be smaller and more able to penetrate our skin.

Join me tomorrow as we take a look at a few cosmeceuticals that include peptides.

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Chemistry: Polysaccharides

I need to break for an aside here on the chemistry of polysaccharides as this is coming up more and more as I research our cosmeceuticals.

What are polysaccharides? They are "polymeric carbohydrate structures formed of repeating units joined together by glycosidic bonds" (from Wikipedia). We can find quite basic ones like two monosaccharides like glucose and fructose joined together to make sucrose or D-galactose and D-glucose joined together to make lactose (the picture above and bane of my existence!). We can find more complicated ones like starch, glycogen, cellulose, xanthan gum, guar gum, hyaluronic acid, and so on. We find a lot of polysaccharides in bath and body ingredients, so it's useful to know what they do.

In general, we use ingredients with polysaccharides as healing, soothing, and skin protecting qualities as they reduce irritation and can create a barrier between our skin and the outside world.

Some polysaccharides are considered mucilagenous, meaning they contain mucilage. Mallow, liquorice, and aloe vera all contain mucilage and this gooey stuff can create a film on our skin to protect us while soothing and reducing inflammation. (As Alton Brown calls it in his episode on okra, it's SLIME!) We can make a form of hair gel by soaking flax seed because of this slime and you can find it in chia seeds and carageenan.

Some polysaccharides are starches - like tapicoa, corn, and arrowroot powders, to name a few. These starches can be used alone in products like dusting powders that can help absorb liquids and prevent chafing, or can be included in our products to bind and thicken, like Dry-Flo. In these cases, the polysaccharides offer the skin protecting, soothing, and healing qualities as well as adding thickness (and often increasing that dry feeling) to the products.

We also find polysaccharides like xanthan gum (picture to the left), guar gum, cationic guar gum, and cationic hydroxyethylcellulose (HEC) that will thicken our products and offer that light film forming. These tend to be quite complicated molecules that can create a film on your skin and make things like lotions, shampoos, conditioners, and other water based products thicker.

And some are humectants, like hyaluronic acid (scroll down a bit after clicking). As a note, glycerin is not a polysaccharide, it's a glycerol.

So if you see that an ingredient like beta glucan or sea kelp bioferment contains polysaccharides, you can extrapolate that this will be an ingredient that offers film forming and skin soothing properties. It may or may not add thickness to the product and that's something to investigate when you are considering the viscosity of a product.

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Fun with chemistry: Anionic, cationic, and non-ionic

Will writes....I'd love to learn more about the whole _____ionic thing and how it applies to lotions/cream, etc. I've read about it, and the more I read the more confused I become. How about dumbing it down and explaining it in your excellent fashion? Just wishing...

Wish no more, Will! When it comes to chemistry, you ask and I will write (and it's not just 'cause flattery works well with me!).

Anionic, cationic, and non-ionic refer to the charge on the ingredient in question. Non-ionic means it has a neutral charge. Anionic means it has a negative charge. And cationic means it has a positive charge.

Take a look at this picture. The head is the thing that carries the charge. If the charge on the head is negative - for instance, something like sodium laureth sulphate with a sodium ion on the head - it will be an anionic ingredient.

If the charge on the head is positive - for instance, something like BTMS-50 - it will be a cationic ingredient.

If the head carries both a positive and negative charge, we get a zwitteronic ingredient (something like our betaines or sultaines, which are also called amphoteric when we're talking about surfactants), which can be positive or negative depending upon the pH level of the product.

This chart really only applies to our surfactants, those with a hydrophilic head and a hydrophobic or lipophilic tail (not just bubbly surfactants, but anything that reduces the surface tension between the two phases of our products, like emulsifiers). If it doesn't fall into the category of surfactants, then we generally have a non-ionic ingredient.

Most of our foaming, bubbling surfactants are anionic or negatively charged. Quaternary cationic compounds like BTMS-50, cetrimonium chloride, cetrimonium bromide, and Incroquat CR, and cationic polymers are positively charged.

In lotions, most of our ingredients are non-ionic or neutrally charged, like our emulsifiers, fatty alcohols (like the cetyl alcohol molecule you see), fatty acids, oils, butters, extracts, hydrosols, humectants, and so on. So when it comes to lotions, we're dealing mostly with non-ionic ingredients.

You can add a cationic ingredient to a lotion - I do it all the time with things like cationic polymers (like polyquat 7, polyquat 10, polyquat 44, and honeyquat) or as our emulsifier, like Incroquat BTMS-50. Cationic ingredients are substantive, meaning they will adsorb to your hair or skin and are substantive. (For more information on substantivity, please click here.) You can add an anionic ingredient to a lotion, but I can't think of any I'd like to add (for instance, I really don't see adding something like SCI to a lotion, despite my love for it!)

You really don't need to worry about charges all that much when it comes to lotions because most of our ingredients are non-ionic and we can easily add some cationics to the mix without fear of any serious problems.

Why add cationic ingredients to a lotion or cream? Generally we add them to a lotion for the skin conditioning benefits (the whole substantivity thing). When we use Incroquat BTMS-50 as our emulsifier or add a cationic polymer to our lotions, we are increasing the skin conditioning features of the lotion (and in the case of honeyquat, we're also adding a humectant, so it's a bonus!)

As an aside, I've said this before but please indulge me for a moment. You cannot have a hair conditioner without a cationic ingredient. The very essence of a conditioner is that it adsorbs to the hair strand and offers substantivity. Without a cationic ingredient, you don't have a conditioner. You might have something else that your hair likes, but it isn't considered a conditioner. 

Do you have chemistry related questions? Ask away! And for more chemistry, please check out the "frequently asked questions" post to the right hand side of the blog!

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A little chemistry on thickening...

Here's a little chemistry to start your day! Let's take a look at colloids, hydrocolloids, and shear thinning.

What is a colloid? A colloid is "a substance microscopically dispersed evenly through another substance." It can be a gas, solid or liquid. It consists of two phases - the dispersed or internal phase and the continuous or dispersed medium. Does this sound familiar? It should because lotions are considered colloids (liquid-liquid colloids)! The dispersed medium or continuous phase is the water phase and the dispersed or internal phase is the oil phase. So you've been making colloids and didn't know it!

What is a hydrocolloid? A hydrocolloid it's a colloid system where the colloid particles are dispersed in water, and it can be a gel or a liquid. If it's a liquid, it's called a sol - a colloidal suspension of solid particles in a continuous liquid medium, like blood or toner (I probably shouldn't have put those two things together - what an association!). The thickeners we'll be discussing like guar gum, xanthan gum, cationic guar gum, and so on create hydrocolloids.

What is shear thinning? We see this phrase thrown around quite a lot in lotion making, but it's applicable to gels and just about everything else we make. Shear thinning refers to a situation where the viscosity of something decreases with the rate of shear stress. It can refer to when we're mixing our lotions - when we're stick blending or mixing it, it will seem thinner than when the lotion is at rest - or to when we're using our products - squeezing a bottle will reduce the viscosity of the product. When we stop applying stress - stop squeezing, mixing, or pumping - the product returns to its original viscosity. (Materials that exhibit shear thinning are called pseudoplastic materials.)

What is thixotropy? It is a property of certain gels or viscous fluids: They become more fluid when we apply stress like shaking or squeezing a bottle. It takes a finite time to attain its original viscosity when introduced to a change in shear stress.

Thixotropic materials see a reduction in viscosity over time at a constant shear rate.
Pseudoplastic materials see a reduction in viscosity at an increased shear rate. Meaning, the viscosity decreases as we apply more stress. If we keep the stress the same, the viscosity will remain the same. With a thixotropic material, the viscosity will reduce over time if we keep the stress the same. Guar gum is an example of a thixotropic material when used at 1% (but not at 0.3%).

So let's get back to our regularly scheduled programming and take a look at guar gum!

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Question: What does "coconut derived" mean?

As people refer me to things they consider to be natural products, I keep seeing the words "coconut derived" beside surfactants, fatty alcohols, fatty acids, and other ingredients that are, in fact, coconut derived. But what does this mean?

Coconut oil is often the starting point for surfactants because it has a fatty acid profile that is very compatible with those ingredients and it's inexpensive. Lauric (C12) and myristic (C14) fatty acids are the types we want in foamy and lathery surfactants - the C12 to C14 chains are the ones most likely to create foam and lather as opposed to the higher carbon chains that behave as emulsifiers or conditioners.

Remember that surfactant doesn't always mean foamy and lathery things we use in bubble baths and shampoos. The word surfactant is short for "surface active agent" and has a hydrophilic (water-loving) head and a lipophilic (oil-loving) or hydrophobic (water-hating) tail. This means it can bring things together like oil and water. So an emulsifier, like emulsifying wax or Incroquat BTMS, is a surfactant.

So when you see a surfactant like sodium laureth sulfate (SLeS), you know that it has been derived from lauric acid, most likely from coconuts but sometimes from palm oil (look at the "laur" in the middle word). Sodium lauryl sulphate (SLS) and sodium laureth sulfoacetate (SLSa) are derived from coconuts. If you see something like sodium cocoyl isethionate (SCI), the "coco" part means it's derived from coconuts. Some of these are very lovely mild cleansers, but one of them - SLS - is not.

Fatty alcohols and fatty acids can be derived from coconuts as well. Myristyl alcohol, found in this Aubrey Organics product, is derived from the myristic fatty acid (C14). Is myristyl alcohol more natural than cetyl alcohol (C16)?

So what does it mean when a manufacturer puts "derived from coconuts" or "derived from sunflower" or "derived from insert some natural sounding thing here". It means the starting point of the ingredient was coconuts or sunflowers or other natural sounding thing, but it doesn't mean that because it's derived from a coconut it contains any of those wonderful things we find in coconut oil, that it's natural, that it's mild (take SLS for an example), or that it's not very processed. In fact, being derived from coconuts means just that - the original starting point of the ingredient was a coconut. I think it's a sneaky way for manufacturers to make their products seem more natural and, therefore, more appealing.

Question when you see something as listed as being "derived from something or other". My favourite example was to see dimethicone and cyclomethicone, both silicones, listed as being "derived from sand" and, therefore, natural. I love my silicones, but I wouldn't consider them natural in any way!

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International Year of Chemistry!

Today marks the beginning of the International Year of Chemistry, as declared by UNESCO and IUPAC (International Union of Pure and Applied Chemistry). This year we'll celebrate chemistry and how it has improved the lot of humankind under the theme of "Chemistry - our life, our future".

2011 was chosen as it has been 100 years since Marie Curie won the Nobel Prize in Chemistry for "[for] the discovery of the elements radium and polonium, by the isolation of radium and the study of the nature and compounds of this remarkable element", so we're also celebrating the role of women in chemistry. (She also win a Nobel Prize in Physics in 1903 with her husband, Pierre Curie, for their research on radiation. Check out this link to see all the Nobel prizes awarded for chemistry. Interesting reading!)

How can you take part in the International Year of Chemistry without having to be a chemistry obsessed geek like me (I'm so obsessed, I married a man named Nichols!)? Learn a little more about an element (although I'm partial to nickel, I also enjoy silicone and sodium). Read a book like The Disappearing Spoon or one of Joe Schwarcz's books and learn more about the every day chemistry in your life. Learn more about a chemist from your home town like Charlotte Froese Fischer (who resided in Chilliwack, and writes about her youth here).

I think we should take this year as an opportunity to show that chemistry is more than blowing stuff up (which is what the boys in my youth group think) or making the world a more horrible place. I think one of the best ways to celebrate the International Year of Chemistry is to take it upon ourselves to help educate those who don't know how much fun chemistry can be! Teach just one person how much fun it is to make a lotion or shampoo or enlighten one person who thinks "chemical free" is a valid concept and we're that much closer to a more science literate society!

Yay for the International Year of Chemistry!

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Adjusting the pH of our products

In some recipes, you'll see the addition of citric acid or sodium hydroxide (lye) at the end to alter the pH of the product. Ideally, our products will be between 4.5 and 7 (there are few products that fall outside these areas, like cold processed soap and some moisturizers with AHAs), and the citric acid decreases the pH, making it more acidic, while the sodium hydroxide increases the pH, making it more alkaline.

For the most part, the ingredients we use are pH balanced, so we don't need to mess around much when making lotions, unless we're adding ingredients like AHAs, but when we're working with surfactants, pH is really important.

As you can see from this recipe in which I'm using new surfactants, the first result brings me to 8.6, which is far too high for a body wash. We want something around 6.0 to 6.5, so I adjusted the pH by adding 0.2% citric acid at a time. It took 0.4% citric acid to bring the pH level down from 8.6 to 6.51, which is a good level for our skin.

As a note, I found that 0.15 cc citric acid equals 0.2 grams, so if you don't have a tiny scale, there's a quick and easy way to include it in our products. 

In my facial cleanser recipe from the Iron Chemist challenge with LSB, I found the original pH of the mixture was 5.16, which is considered acceptable for our skin's pH range. But I thought it would be fun to try to increase it slightly with the failed batch. I could have used sodium hydroxide (lye) at 10% dissolved in 90% water and add it bit by bit, but I figured this could use more surfactants, so I chose the high pH surfactant decyl glucoside to the mix. 10% decyl glucoside brought the pH to 5.6, so you can see there's quite a change when you use an alkaline ingredient.

If you want to increase the acidity of your product (reduce the pH), I recommend using citric acid at 0.2% a little at a time to decrease it by about 0.9 or so. (It isn't a hard and fast rule that it will reduce it by 0.9 at a time; this was just my experience. It will depend upon the pH of your product, what kind of product it is, what ingredients you've used, and so on.)

If you want to increase the alkalinity of your product (raise the pH), you can use a 10% lye to 90% water solution and add it at 0.1%, test, then another 0.1% if needed, and so on. You can also use triethanolamine (TEA) (pH of 10 to 11) at 0.1% at a time to increase the alkalinity of our products.

Or you can use our ingredients to change the pH level. Adding something like an AHA will decrease your pH, while using a higher pH surfactant - like decyl glucoside or disodium cocoamphidiacetate - will increase the pH.

As a note, if you've made gels with carbomer, you're familiar with the idea of increasing the alkalinity of the product - add some TEA or 18% lye solution to your carbomer and you've got a gel! 

Can you tell I'm having fun with my pH meter yet?

As a final point of interest, did you know the term "pH balanced" in commercial products doesn't have a legal definition, so it can mean just about anything. It can mean "pH 5.5, which is around our skin's pH balance" to "blah blah blah". It's on par with saying your skin "appears cleaner", which doesn't actually mean your skin will be cleaner. There's a dental ad on TV right now that claims your teeth will "appear cleaner" but there's no reference point - for instance, appears cleaner than not using a toothpaste at all or another brand of toothpaste? So it really means nothing! And don't get me started on the conditioner ads that have the little asterisk at the bottom of the screen to indicate that they're comparing the state of your hair without using a conditioner (Pantene does this all the time). We all know that using a conditioner will make our hair softer and in better condition! Oh, I didn't realize I was off on a rant again...I better stop. 

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SNOW DAY!

It's a snow day! The schools, my husband's university, and my work are all closed today thanks to the almost 30 cm or 12 inches of snow we've had fall in the last 11 hours. The roads are treacherous and it's too dangerous to go out today. So SNOW DAY! (And tomorrow's going to be worse with freezing rain predicted to add that crunchy layer to the powder! EEK!)

Traditionally, Chilliwack has used salt to clear our roads as it is good to about -18˚C or 0˚F (and it rarely gets below -7˚C around here), but this year they've started using a different concoction, one that includes propylene glycol or other glycols to reduce the freezing point of water (other communities have used this type of thing for years, but we're finally getting around to it!).

As a note, most of our humectants can work as de-icers by reducing the freezing temperature of water, but I don't think you want to throw a ton of Hydrovance onto your windshield any time soon (mainly due to cost). 

You can also use different types of salts to melt snow or weaken ice. Good old sodium chloride (NaCl, known as table salt or rock salt) will work because a brine solution (water mixed with salt) will lower the freezing point of water, but it can cause a lot of rust on our cars and corrosion in other metallic things. Calcium chloride (CaCl2) is being used a lot lately because it doesn't have the same effect on the environment (although it's not very evergreen tree friendly) and because it is good to really low temperatures (we're talking -52˚C or -82˚F as opposed to -18˚C for NaCl).

Unfortunately, no matter what de-icer you use, there are consequences for our environment. Urea can break down into ammonia, which can be toxic for animals. Salt can cause corrosion, and calcium chloride can upset our trees, and propylene glycol takes a long time to biodegrade and consumes oxygen as it breaks down.

See, even a snow day can be made more interesting with chemistry!

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Sapogenins

Okay, so we know all about saponins - from yesterday's post - so let's take a look at sapogenins and how they differ.

If you'll recall from yesterday, a saponin contains two parts - the glycone, which is the sugar part, and the aglycone, which is the non-sugar part. When a saponin undergoes hydrolysis, the aglycone is now called a a sapogenin. (Hydrolysis is a chemical reaction in which a molecule is cleaved into two parts by the addition of a water molecule - "hydro" is water, "lysis" is splitting").

There are two main types of sapogenins - steroidal and triterpenoidal. (You might recall that saponins are triterpenoid glycosides. When we take away the glycoside or sugar part through hydrolysis, we're left with the triterpenoid part.)

Steroidal sapogenins are used in commercial production of sex hormones - for instance, progesterone is often derived from diosgenin from fenugreek.

Triterpenoidal sapogenins are of great interest to us as bath and body formulators because we find them in quite a few of our ingredients. Liquorice root contains glycyrrhizinc acid, which can behave as an expectorant and flavouring ingredient, as well as a strong anti-inflammatory. Quillaia bark can behave as an emulsifier. And gingseng contains ginsenosides, which are good anti-oxidants and are showing promise for anti-tumour growth.

For the most part, triterpenoidal sapogenins are good anti-inflammatories and may be good anti-oxidants.

So there you have it...a crash course in terpenes, saponins, and sapogenins. So what's the point? First, it just shows how amazing some of our botanical ingredients can be. Two, I thought it was interesting, especially the bits about natural emulsifiers and surfactants. And three, we can never know too much about the ingredient we're using.

As a note, I do not know how to make emulsifiers or surfactants from any of the plants I've named, so please don't ask how to make an emulsifier out of Quillaia bark because I don't know. I just wanted to share some interesting chemistry with you as we get ready to ring in the new year!

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Saponins

With all this talk about natural emulsifiers and surfactants, I thought we'd get into a little chemistry about sapogenins and saponins! 

Saponins are steroid or triterpenoid glycosides that have amphiphilic or amphipathic features. They are grouped together by having "soap like foaming qualities they produce in aqueous solutions" - in other words, when you put them in water and shake them up, they foam. What the heck does this mean? Let's break it down...

Amphiphilic or amphipathic compounds are those that possess hydrophilic and lipophilic properties. Sound familiar? Yep, they're surfactants! They have one end that likes fat and another that likes water, so they can bring oils and water together to produce emulsification! Some of them also foam, which makes them like our lathery surfactants (Quillaja, soapwort, and Indian soapwort fall into this category).

Glycosides are molecules in which a sugar is bound to a non-carbohydrate moiety (functional group), usually a small organic molecule. The sugar group is known as a glycone and the non-sugar part is known as an aglycone or genin. If the glycone group is a glucose, then the resulting glycoside is known as a glucoside. If the glycone group is fructose, then the resulting glycoside is known as a fructoside.

One alcoholic glycoside we see a lot is salicin from the willow tree, which is converted into salicylic acid in our bodies. You can see the O-glucosyl part is the sugar part (the glycone) and the rest of the molecule is the aglycone.

The flavonoid glycosides are ones where the aglycone or non-sugar part is a flavonoid that behaves as an anti-inflammatory, anti-oxidant, and anti-microbial properties. Some of these include rutin and quercetin as the aglycone part.

So a saponin is a molecule to which a sugar is bound that can behave as a surfactant. It could be a foamy surfactant or an emulsifying surfactant, but it's something that can reduce the surface tension of water. We see it being used as an emulsifier in this Dr Bronner lotion (click here for the comment by p that started this mighty research journey) and we are seeing these saponins being used in a variety of natural cosmetics.

Most of these saponins dissolve easily in water and are poisonous to fish. There is a long history of fish-poisoning by saponins by indigenous tribes around the world. They are also known to kill protozoa and molluscs, impair digestion of protein and uptake of vitamin and minerals, cause hypoglycemia, and can behave as anti-fungals, anti-virals, and anti-oxidants. (Link here.)

An aside with a few of my thoughts: This could make for interesting preservatives, but it doesn't seem like anyone is using them in this fashion. As well, are these all natural surfactants any better than synthetically produced surfactants? If they're killing fish and molluscs, isn't this kind of defeating the purpose?

Join me tomorrow for more chemistry fun with saponins!

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Terpenes

So what the heck are terpenes? We see them mentioned a lot in information about essential oils, but what are they and do they benefit us as bath and body formulators in any way?

Terpenes are organic compounds, the major building blocks within nearly every living creature. For instance, steroids are derivatives of the triterpene squalene. (Quote from Wikipedia .) They are derived from units of isoprene (that's the picture up there, with a formula of C5H8) called the isoprene rule or C5 rule. Terpenes are created out of multiples of those isoprene units. When they are modified chemically through oxidation or rearrangement of the carbon skeleton, they become terpenoids or isoprenoids (terpenoids are not the same as terpenes as they have been modified in some way, but some people group them together.) These can be cyclical or linear.

Terpenes are everywhere in our products, especially in oils and essential oils.

MONOTERPENES
These contain 10 carbons and 2 isoprene units. They tend to be used as flavouring and fragrancing ingredients, but they often have other great qualities. Limonene is a great example of a monoterpene, and we know it acts as a good degreaser (you can see the isoprene unit at the top and bottom of the ring). Linalool, which is found in roses and lavender, is often used as a fragrance ingredient. Other monoterpenes of interest are camphor, menthol, citronellal, thymol, and carvacrol.

We find major monoterpenes in plants or spices like black pepper, peppermint leaf, cardamom, rosemary, bitter orange peel, camphor, caraway, and thyme.

Some monoterpenes can stimulate mucous membranes and help with congestion, respiratory issues, and phlegm - think about Vick's for a moment with the camphor, eucalyptus, and menthol (but don't think about Buckley's cough syrup because it really tastes awful!). You'll find 1,8-cineole (aka eucalyptol) in tea tree oil and eucalyptus, both of which can stimulate mucous membranes but can be irritating at higher levels. And there is some indication that monoterpenes might have some anti-cancer properties (click this link for the summary of the study).

SESQUITERPENES
These contain 15 carbons and 3 isoprene units. They are found abundantly in plants and some of the major ones are alpha-bisabolol in chamomile and parthenolide in feverfew, both of which are potent anti-inflammatories, and ß-caryophyllene (the picture to the left), found in rosemary, cloves, cinnamon, and the essential oils of cannabis. Studies are still testing to see if the the ß-caryophyllene has anti-inflammatory properties in humans.

Another important sesquiterpene is farnesol, found in citronella, neroli, lemon grass, tuberose, rose, musk, and balsam. It's used in products to enhance the fragrance, but it's also a natural pesticide for mites and is active against yeasts.

For more on sesquiterpenes, click here.

DITERPENES
These have 20 carbons and 4 isoprene units. The most significant one is phytol, which constitutes the lipophilic side chain of chlorophyll in plans. It forms a part of Vitamin E (tocopherol). (Vitamin A contains 20 carbon atoms but it's formed from a cleavage of a tetraterpene.) Some of the other important diterpenes are stevioside from stevia (which I enjoy in my tea every morning) and ginkgolides from ginko.

TRITERPENES
These contain 30 carbons and have 6 isoprene units. The most important one is squalene, which makes up about 12% of our skin's sebum, so our skin identifies it as "ours" and soaks it up quickly. Squalene is a vital part of cholesterol, steroid, and Vitamin D synthesis in our bodies. It penetrates the skin quickly offering softening and moisturizing to even really chapped or cracked skin.

We find it in lanosterol, one of the ingredients in Croda's Super Sterol product.

In this category we also find curcurbitane, which is found in cucumber extract, and is a very good anti-inflammatory and analgesic. And we also find dammarenediols in ginseng extract, which might help with penetration of actives into our skin. (As a note, ginseng extract contain saponins, which we'll be looking into tomorrow.)

TETRATERPENES

These contain 40 carbons and 8 isoprene units. The major tetraterpenes of interest in this category are ß-carotene, lycopene (pigment in tomatoes), and capsanthin (pigment in red peppers)

So why am I sharing this all with you? First, chemistry is awesome. Second, if you want to learn more about saponins, which are natural surfactants, you need to know a little about terpenes. And third, these show up in our oils and essential oils all the time!

Join me tomorrow for fun with saponins!

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