Swimming towards the dark: a photophobic light-driven elastomeric swimmer – Peter Palffy

Date: Mon. April 14th, 2003, 12:30 pm-1:30 pm
Location: Rockefeller 221

Liquid crystal elastomers are characterized by strong coupling between orientational order and mechanical strain; optical excitations that result in a change of the order parameter can therefore bring about large mechanical deformations. We have studied the optomechanical response of nematic liquid single crystal elastomers doped with an azo dye.

Our recent experiments have shown a fascinating interaction between light and elastomer samples floating on the surface of a fluid: When exposed to laser light, the samples change both their conformation and position – they swim away from the illuminating light. The observed dynamics is unusal in that it is predicated on the transfer of information as well as energy from the light source to the swimmer. To understand this behavior, we study the interactions of a deformable and active “solid” with surrounding liquids, and examine the details of momentum, energy and information transfer. Understanding the interactions between active bodies and fluids can give insights into the fluid dynamics of swimming, and help enable the construction of artificial swimmers using this novel propulsion mechanism.