By: Tina Coop and Priscilla Nguyen A closer look at the flow patterns of shampoos, conditioners, and gels.

Terminology Definitions of Critical Words Rheology - Study of the deformation of materials. Rheometer - Instrument that measures the deformation of materials. Viscosity - Resistance to flow or fluidity (shear stress/shear rate). Elasticity - Power to reform after an amount of stress. Shear Rate – The rate at which deformation is applied (measured in 1/s). Shear Thinning - When viscosity decreases as rate increases. G’ - Elastic modulus G” - Viscous modulus Frequency - Oscillations per unit time. Cross-over Point - A point in which the moduli extend over each other and the fluid changes properties. Newtonian Plateau - An area of constant viscosity. Polymer – A component of hair products (literally meaning ‘many parts’).

Equipment The machine and the tools that we used in the experimentation. In our experiment we used a Bohlin Rheometer in a cone and plate geometry. The cone was 4 degrees and had a 40 millimeter diameter. We used two types of tests and in the steady test, the cone rotated atop the sample and then rotated left to right in the dynamic test. To load samples we used a simple syringe with the needle removed.

Procedure Step-By-Step Process in Testing Samples Fill syringe with sample (about 1.5mL) Put on geometry Zero the machine and set the gap to.15 mm Load the sample Lower geometry (locked in place) Make sure fluid isn’t ‘pooling’ by scraping off excess Open the Bohlin program on the computer Choose the type of test. (Steady/viscometric or dynamic/oscillation) Set the rate at cycles/sec. on viscometric tests and Hz on oscillation tests Select correct geometry in program Start the program

Fructis has a higher initial viscosity All start shear thinning at the rate of 10 1/s

White Rain has no crossing point The three that did cross, crossed between 1-10 Hz Herbal has a lower crossing point Pantene and Fructis have the same crossing point

White rain is a deviant, it has a lower viscosity then the rest All have a similar slope

The slops are basically the same The products are extremely similar in flow properties

All have a Newtonian Plateau (other than the conditioner) The shampoos show shear thinning

All shampoos meet at a cross-point. G’ and G’’ have similar slopes in conditioners Gels are more elastic than viscous

Analysis What we see the tests have shown. Shampoo All have shear thinning and start shear thinning at about 10 cycles/sec. White Rain was cheapest yet it showed the same flow properties of other shampoos In dynamic tests, White Rain was the only shampoo without a crossing-point and the ones that did, crossed between 1-10 Hz. Volumizing shampoo Eventually they all have the same viscosity at higher rates. Volumizing shampoo has similar flow properties as regular shampoo in both tests Conditioners The White Rain is a deviant; it has a lower initial viscosity than the other conditioners Conditioners have non-Newtonian behavior At low stress (1Pa) all conditioners are more elastic than viscous Conditioners were hard to test because they slipped, so re-running a sample was common. 2 in 1 Shampoo and Conditioner They all have Newtonian plateaus. 2-1’s act like shampoos at low rates and conditioners at higher rates. 2-1 look like shampoos more than conditioners in dynamic tests.

Conclusions In the end we think... We’ve deducted many things during this experiment and believe that: Shampoos and volumizing shampoos have similar properties 2-1’s show properties of both a shampoo and conditioner Gels are more elastic than viscous Shampoos change their properties at higher rates Conditioners are non-Newtonian fluids Shampoos will always have a cross-over point Gels and conditioners are similar and have slopes that are alike in their nature Conditioners appear to have higher initial moduli than gels

Special Thanks Here at SESEY we’ve enjoyed the wonderful experience and opportunity of being here and would like to thank the following people: Dr. Skip Rochefort – Thank you for providing us with a special opportunity and sharing your knowledge. Because of you, we have a greater understanding of engineering and what it can provide us. Samantha and Amy – Thank you for being our mentors and our guide through our project. We know so much more and wish you the best as we know you would the same. Everyone Else Who Was Here: THANKS! You all made our week the perfect journey and you didn’t even know us and we are grateful for that.