[Abdullah]

Pharma said:

I don’t think that you would buy the books I have because most of what they cover is overkill unless you study pharmacy… there are many books explaining zeta potential. Even Wikipedia might help .

Yes, lower pKa means more anionic emulsifier is actually anionic (= dissociated) at a given pH. Sulfates like SLS are kind of an exception because of the very low pKa which renders them 100% anionic under all ‘normal’ conditions. SLES has a similarly low pKa. SSL and GMS citrate are not chemically well defined. It is safe to assume that SSL has a similar pKa than lactic acid and GMS citrate the lower two pKa values of citric acid. However, GMS citrate is not used as salt but in undissocitated form and might not deprotonate as much as would be expected. Some suppliers even list their GMS citrate - fatty alcohol blends as nonionic emulsifiers.

Thanks a lot

[Abdullah]

[Abdullah]

@chemicalmatt what percentage of SPDMA minimum is needed for salt response and in what range of salt additional does it increase the viscosity?

I did make an emulsion with 0.5% SPDMA and added up to 0.08% NACL but didn’t get any viscosity increase.
This was my formula

[Abdullah]

Preservative is not enough. And i think you don’t have emulsifier 

[Abdullah]

Pharma said:

You’re asking the wrong question .
Hopefully i am getting the right answers anyway ????.

A. Surfactant charge can increase emulsion stability but usually, it’s the charge of the interface (called zeta potential) which has a tremendous effect on emulsion stability.

B. Zeta potential can be influenced by many factors. Read a book.
any book suggestion that i should read?

C. Influencing a charge of an anionic emulsifier/surfactant is basic chemistry. It boils down to pH and pKa. What does affect pH? Acids and bases. Does that directly translate to emulsion stability? No, it does not but it can.
does the one with lower PKa has higher charge?

pka of SLS is -1.5 but i could find PKa of SLES, SSL and GMS citrate. Do you know how much they may be?

The efficacy of an anionic emulsifier doesn’t solely depend on pH. Some anionic emulsifiers like SLL may work differently at a pH of 4 than they would at a pH of 6. 
i once did reduce the pH of SSL emulsion to 4 and it became grainy. I was using stick blender.  I don’t know if it will be different with homogenizer because i only have homogenizer for large batches.
 Whether or not this is affecting emulsion stability depends on the whole system.

 

[Abdullah]

Pharma said:

The incompatibility of parabens has something to do with overall structure (especially the aromatic part) and is a thing of observation because there is no clear scientific explanation why and how.

Ionic interactions like benzoate with cationic emulsifiers clearly depend on the charge.

Thanks

[Abdullah]

Pharma said:

Half the ingredients shown are at 0%….

Why do you add NaCl?

This is EXEL fill that i use to work with. I have listed all the ingredients that i have and can use in emulsion here ????.

Make different samples with different ingredients from list. In this sample i used the ingredients that i have written the quantity of them.

It is said that NACL at small quantity increases the viscosity of cationic emulsion. I i made a 1% solution of NACL and added but didn’t notice viscosity change.
It is 0.08% NACL here. 

[Abdullah]

I have done it too and it worked. If you add it to high surfactant product like sles or CAPB it doesn’t blend, but in pure water it should. 

Do this.

Just add PQ10 to water, mix and see if it is completely solubilized. If yes the add other ingredients. If no then report here to talk about it. 

And don’t forget to take picture so we can see why it is not working

[Abdullah]

suswang8 said:

Hi, all.

I already slurry it with my glycerin, but I thought that this facilitates dispersion, not hydration?  Basically, you all seem to be saying to add it into the water phase (not after the emulsion is made) and that there is no need to wait to ensure the gum is fully hydrated?

Yeah. Xanthan gum no need to wait

[Abdullah]

Maybe at 100%. But at 0.5% not

[Abdullah]

AZIZ_KALUNGI256 said:

PhilGeis said:

As Pharma noted - sorbate/benzoate concetrations are too high  - drop each by 50% - and you don’t need both.  Suggest addition of phenoxyethanol.

In production, the water phase will grow microbes if you let it sit around.

Thanks.  I will try to source phenoxyethanol. 
Its rather scarce over here though

How do you know what scares people?
In my opinion asking people what is scaring you is not a good idea.

The best way to know is to check what preservative does the big companies, most popular products that majority of people in your area purchases use. This way you van know majority of people aren’t scared of that preservative. 

[Abdullah]

Mixing it with preservative or your fragrance or oil phase all works. And you don’t need to wait.

[Abdullah]

@Pharma anionics like sodium benzoate doesn’t work well with cationic surfactants like SPDMA. Will it be the same for methyl Paraben at pH 4-5?

How “Incompatibility has nothing to do with ‘ionic charge’.”?

[Abdullah]

Pharma said:

Naw, the structure determines how strong an acid is (the value used is the pKa). However, if a molecule carries more than one acid functionality, each additional one has a lower strenght. Citric and phosphoric acid with three acid groups each has three different pKa values for ‘pronon’. This is due to an increased charge once the first functional group is deprotonated, the created negative charge reduces the acidity of the other remaining ones and so on.

Thanks a lot

[Abdullah]

@Pharma got it ????????.

Just didn’t get this part that what makes an acid stronger or weaker. 
Does less chare make an acid stronger or what makes it? 

[Abdullah]

“Conditioning Agents for Hair and Skin” I liked this book so much that i studied the whole book in one day. I didn’t want to stop reading it????.

[Abdullah]

@Pharma does having less carboxylic acid group mean Stronger acid? 

[Abdullah]

ketchito said:

@Abdullah Styrene/acrylates opacifiers don’t require suspending agents. 

Common emulsion are macroemulsions (that’s why they are white; microemulsions are transparent). 

Thanks ????

[Abdullah]

TheStrand said:

Abdullah said:

Does it mean if we mix 2g aloe Vera powder with 98g water it will be like aloe vera juice?

No, that’s actually exactly what we were just discussing. The dehydrated powder does not maintain many of the biomolecules and rehydration does not restore the lost components. This is exactly why I’d rather preserve it in its original water based state as long as possible.

Interesting
Thanks

[Abdullah]

@ketchito do we need suspending agent for styrene/acrylates? 

And is the common emulsions (lotion and cream) macro emulsion or micro emulsion? 

[Abdullah]

@Pharma is it because of charge density that 1 M salicylic acid gives less acid that 1 M citric acid?

If yes then what does it do that is is considered strong acid than citric acid? 

[Abdullah]

Add PQ10 to water before adding surfactants. 

[Abdullah]

Perry said:

Thanks for your question.  Just some thoughts

If you are really looking to make it last “as long as possible at room temperature” then using synthetic preservatives is the way to go. Parabens to fight against mold & fungi and aldehydes to fight against bacteria.  

But I suspect you don’t really mean “as long as possible.”  Rather you want to know how to make it last as long as possible “without using standard preservatives.” Correct?

Well, your options are limited. Microbes are great at contaminating things & nature hasn’t evolved broad spectrum based ways to stop it. See the recent discussion here about natural preservatives.  You’ll have to decide for yourself what you consider natural enough.

While you’re not a chemist you would find it helpful to develop an understanding of what Aloe Vera Gel is & what it has been demonstrated to do (not just claimed to do). This article may be helpful. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551117/

In that article you’ll find that Aloe is made up “of more than 200 bioactive chemicals“. But it is also made up of 98% water. Even if you dilute it with 2:1 aloe:glycerin there is still going to be a >30% water in the system. Tocopherol is not a microbial preservative so it will have zero effect. Glyceryl Stearate is not a preservative either and will have no impact on microbial contamination.

HEC is certainly an option to provide a consistent texture. However, it is a chemically modified ingredient and does not occur anywhere in nature. Is that natural enough?

In science, there is a reductionist philosophy where when you find a substance that has an effect, you try to figure out what component of that substance is giving the effect. Then you try to create a product that will maximize the effect while minimizing components that reduce or have no impact on the effect. 

Synthetic cosmetics were created because the natural stuff found out in the world is not nearly as nice or effective as the synthetic stuff. (e.g snotty gums).

Does it mean if we mix 2g aloe Vera powder with 98g water it will be like aloe vera juice?

[Abdullah]

@Pharma thanks ????

Which one is stronger acid? Salicylic acid or citric acid?
In a comparison at same percentage citric acid reduced the pH of a Shampoo more than salicylic acid. 

[Abdullah]

@ketchito how to create a micro emulsion by my own?

Is there any cold process opacifir?