Crystal Poison.

Crystal Poisons and their effect on wax crystallzation .

California SCC – May 2014

Crystal Poison

What is a CRYSTAL POISON?

Crystal Poison is any compound that retards the crystal formation of a compound that would normally exist in a crystalline state at a given condition.

Crystal Poison

Everday examples of crystal poisons are: Anti-freeze Proteins (AFP’s) which are found in fish that live

in extremely cold conditions. Without AFP’s liquid and fats in these fish would solidify. AFP’s are being looked at for use in foods such as:

meats, vegetables (tomato, cucumbers etc)

Glycols in aqueous based systems for suppressing freezing point of water

Butylene Glycol in emulsions for F/T stability

Crystallization

Crystallization involves two discreet steps:

Nucleation

Crystal Growth

Nucleation

There are two types of nucleation Homogeneous

Uniform relatively pure substances

Nucleation is random and spontaneous

Lowering of temp will initiate nucleation

Heterogeneous Usually impure materials

Needs initiator Wall of a beaker etc

Nucleation

For nucleation to take place, a state of supersaturation has to exist

Molecules aggregate and clusters are formed

Once a cluster is formed, one of two things happen

Cluster becomes unstable and re-dissolve

Cluster reaches a critical size, become stable and a nucleus is formed

Nucleation

Nucleus Molecules

Aggregates

Crystal Growth

Once clusters reach a critical size, and an arrangement in a defined periodic manner is reached, a crystal is achieved.

The crystal then becomes the convergence point for successive layers –like an onion

Growth is influenced by several factors Temp Pressure Surface tension Shear/agitation

Crystal Growth

Once crystal growth begins, two distinct steps are involved:

Formation of an amorphous aggregate of soft wax

And a progression to a more ordered hard wax phase

Crystal formation

Interlocking crystals to form micro-structure

Nucleus

interlocking crystal

Interlocking crystal

Interlocking crystal

Interlocking Crystal

Crystal Poison

So what is a CRYSTAL POISON?

Crystal Poison is any compound(s) that retards crystal formation of a compound that would normally exist in a crystalline state at a given condition.

Crystal Poison – Mode Action

Crystal Poisons have a few modes of action:

Retardation of nucleation

Initiation of multiple nucleation sites

Retardation in the growth of successive layers

Decrease in the crystal size

Steric hindrance

Crystal Poisons – Steric Hindrance

How does steric hindrance work: They lower the cohesive energy which is the

driving force of the ordering transformation When solution temp approaches the cloud point,

wax molecules start to gather together to form wax aggregates

Wax aggregates incorporate wax inhibitors (crystal poison).

Once the inhibitor (Crystal Poison) is incorporated into wax aggregates, a perturbation occurs which retards the transformation of soft wax (micro-clusters) to hard wax (macro-clusters)

Crystal Poisons – Steric Hindrance

Steric hinderance to crystallization

CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH

Stearic Acid (C18H36O2)

CH2-CH2-CH2–CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH

CH3

Isostearic Acid(C18H36O2)

Crystal Poison – General Structure

Comb-type structure

Crystal Poisons – Typical Structures

Typical structure of molecules that sterically hinder crystallization:

Block Polymer with comb structure EVA

Some polyglyceryl esters

Metal soaps

Aluminum

Alkyl Phosphate

Lecithin

Crystal Poison

Steric interference to crystal deposition

Nucleus

interlocking crystal

Crystal Poison -Ecstasy

Iron Oxides 3.5

D&C Red #7 Ca Lake 2.0

Titanium Dioxide 4.0

Oils 30.0

Beeswax 5.0

Candelilla 7.0

Carnauba 6.0

Water 15.0

Glycerin 1.0

Crystal Poison – Pain

D&C Yellow #5 Al Lake 3.5

D&C Red #7 Ca Lake 2.0

Titanium Dioxide 4.0

Oils 30.0

Beeswax 5.0

Candelilla 7.0

Carnauba 6.0

Water 15.0

Glycerine 1.0

Crystal Poison – science is logical

D&C Yellow #5 Al Lake 3.5

D&C Red #7 Ca Lake 2.0

Titanium Dioxide 4.0

Oils 30.0

Behenyl Beeswax 5.0

Cetearyl Candelillate 7.0

Carnauba 6.0

Water 15.0

Glycerin 1.0

Crystal Poison - unmasked

What happened??

Al(OH)3 + Fatty Acids Al-soap

AL

>130C

Utilizing Crystal Poison in Formulations

Crystal poisons can be very useful in formulations, for example:

High conc of waxes in mascaras, without high viscosity, which leads to greater build on the lashes.

Liquid lip products with high conc of waxes

High SPF values