Conditioning Polymers for Hair and Skin: Natural or Synthetic?

Conditioning Polymers for Hair and Skin: Natural or Synthetic?

April 15, 2015

Unless you use a clarifying shampoo designed to strip any potential build up of silicones, oils or polymers, you are almost certainly using a two-in-one conditioning shampoo containing polymers.  The same type of polymer is used in body wash, baby wash, and liquid hand soap.  These polymers are all cationic in nature.  There are a few modes of action that can be used to accomplish the desired conditioning.

Modes of Action

Substantivity – Because skin and hair are slightly anionic in nature (negatively charged). Polymer, which is cationic, is deposited on the hair or skin during rinsing and provides conditioning on its own.

Coacervation – As a surfactant system is diluted, as during use and rinsing, the concentration of surfactant drops below the CMC.  At this concentration surfactant molecules are in solution as individual ions.  The cationic polymer then forms a complex (coacervate) with the disassociated anionic surfactants which entraps the silicones or other oils and deposits them on the hair or skin providing enhanced conditioning.

Natural Polymers

Used for both hair and skin conditioning, Naturally-based polymers are based on natural polysaccharides.  These are typically either cellulose or guar modified with quaternary ammonium compounds.  Cellulose is a polysaccharide derived from wood or cotton (INCI:  polyquaternium-4 or polyquaternium-10).  Polysacharides can also be derived from the guar beans which can then be modified with the same quaternary ammonium compounds (INCI:  guar hydroxypropyltrimonium chloride).  Both of these are made from NATURAL polymers and provide conditioning and ease of combing on hair.

There are variations of molecular weight and cationic charge that effect viscosity, deposition and possibly clarity.  Controlling the level of deposition of polymers and silicone is one way of controlling the potential build up or weighing down of hair.

Synthetic Polymers

There is a variety of synthetic polymers available primarily using polyacrylates as the building block modified with quaternary ammonium compounds.  These tend be used more for skin care than hair conditioning (INCI names include polyquaternium-7, polyquaternium-11, polyquaternium-51 and polyquaternium-55).  Some of these work better in conditioning skin during repeated washing as in hand soaps, others can form films that can help hold moisture in skin when used in facial cleansers.

Whether you decide that you want a natural or synthetic conditioning polymer for your shampoo, body wash or facial cleanser, you can select the product which provides the right conditioning, synergy with other ingredients, after-feel, and long-term aesthetics.  This is barely an introduction to this area.  There is plenty of additional information available.