Paradoxical Damage Enhancement by Conditioning Agents. CA SCC Tycho Speaker PhD 27 March 2014

Transcription

1 Paradoxical Damage Enhancement by Conditioning Agents CA SCC Tycho Speaker PhD 27 March 2014

2 Framework Background observations and methods Macroscopic hair damage Split ends, frayed areas, microfibrils Secondary effects tangles, lint, fuzz, cyclical damage Deposition of Conditioning Agents Hydrophobic vs charge-driven, volumizing Charge effects and paradoxical damage enhancement Total charge vs charge density Charge deposition Damage amplification effects. Mitigation of charge effects Distributing total charge, hydrocolloids, counterions, repair particles Conditioning vs repair Repair technology and reduction of charge effects

3 Background: observations This talk grew out of work with polyamphoteric functionalized microparticles for damage repair. During product development of shampoo and conditioner products, cationic agent anomalous effects were encountered. Speculative model for this effect centers around deposition at negative sites by cationic agents. There are no bad conditioning agents, but complex interactions deserve attention.

4 Background: methods Human hair (caucasian) samples from salon Existing damage culled from trimmed ends New damage created with crush+abrasion Samples end-mounted on 3M Transpore tape Wash/Rinse + Conditioner/Rinse + Blow Dry Wash in 5% SLS solution (5s), Rinse (5s). Condition in 1% conditioner (5s), Rinse (5s). Blow dry high setting 8 distance (35 C).

5 Background: methods AmScope SM-3B 7X-47X dissection microscope (5-45X) Canon EOS T5i with hair ends suspended in free space Ring LED illuminator positioned off-axis at a 45 angle Black paper background Samples were photographed after a single SLS wash, and then photographed again after additional wash + conditioner treatments. Commercial premium conditioning formulations as well as individual conditioning agents (1% aq.) were tested.

6 Macroscopic Hair Damage

7 Snags and Fiber-binding

8 Damage is self-replicating Snags and tangles are directly associated with macro damage. Comb-through of tangled hair produces stretching injury to hair structure along the entire length of the hair. One snag can produce microfractures and incipient damage across multiple hairs. Reduction of snags and tangles is an important component in long-term product benefits.

9 Structure of Hair Figures adapted from Chemical and Physical Behavior of Human Hair, 5 th Ed., Robbins, C.R Springer.

10 Structure of Hair 18-methyl Eicosanoic Acid Figures adapted from Chemical and Physical Behavior of Human Hair, 5 th Ed., Robbins, C.R Springer.

11 Deposition of Conditioning Agents Conditioning agents deposit by hydrophobic association and by charge-driven mechanisms. Healthy, intact hair is hydrophobic, and here deposition is primarily by this mechanism. Damaged hair offers anionic sites at oxidized disulfide bonds. Deposition onto damage is dominated by the much stronger chargeinteraction mechanism.

12 Conditioning Agents and Charge Simple quats like cetrimonium chloride are singly charged and low molecular weight. These diffuse and deposit rapidly. Poly-quats can be thousands of times as large, and may have lower or higher levels of substitution with many charged sites. Deposition from polyquats can load a single anionic site with many positive charges.

13 What happens when you charge hair? Like charges on strands repel each other.

14 Frayed hair before any treatment

15 Same hair after 5% SLS wash + rinse and blow dry as described

16 5% SLS wash + rinse, premium conditioner + rinse

17 Synergistic and Antagonistic Effects Damage can be enhanced by cationic (+) materials like quats and especially highly charged polyquats. Quats are essential for conditioner performance, and these polyquats play important roles. Charge-amplification effects can be mitigated by use of low charge-density polyquats and hydrocolloids while reducing use levels of very high charge-density components.

18 5% SLS wash + rinse, premium conditioner + rinse

19 5% SLS wash + rinse, mitigated conditioner + rinse

20 5% SLS wash + rinse, mitig cond + repair particles + rinse

21 Same hair after treatment with leave-in product with repair particles

22 5% SLS wash + rinse, premium conditioner + rinse

23 Enlarged view: deposited charge reveals fractal-like damage structure

24 Conditioning vs Repair Conditioners have traditionally played the role of finishing hair after washing, to restore a healthy, youthful state. Modern products frequently include repair in claims language, recognizing the role of damage in hair aging and appearance. Products that include functional repair during shampoo can make charge amplification effects irrelevant, as damage sites are sealed.

25 Take home points Current conditioner formulations produce some undesirable effects at damage sites. High charge density and high total-charge appear to be major contributors to these effects in the absence of moderating factors. Charge overloading effects at damage sites can be tempered by use of low charge-density macromolecules and counterions.

26 Thanks Thanks to The Society TCR Industries for sponsorship Capsulent and Earth Supplied Products staff Inquiries regarding this work and kerabead repair particles can be directed to the presenter at