Dynamics of PEO-PPO-PEO and PPO-PEO-PPO triblock copolymers at the air/water interface upon thermal stimulation

Dynamics of PEO-PPO-PEO and PPO-PEO-PPO at the air/water interface upon the rmal Stimulation is studied with a fast surface light scattering (SLS) tech nique, in terms of the dynamic surface tension recovery relaxation of the c opolymer solutions in response to a short-pulsed temperature jump. The char acteristic of the surface tension relaxation is examined pertaining to the structure, molecular weight, and concentration of the block copolymers at t he air/water interface. The surface tension relaxation time of the copolyme r surfactants is found to be monotonically related to the molecular weight of the PEO blocks suggesting that thermal sensitivity in surface tension of the copolymer solutions be due to a conformation change of PEO chains in t he copolymers at the air/water interfaces upon the temperature change.