Self assembly of nanoscopic structures in 2-D using diblock copolymers: Effect of blending with a dye

CHED 334

Taylor Neiman, tneiman@HMC.Edu and Shenda M. Baker, shenda_baker@hmc.edu. Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711
Amphiphilic diblock copolymers are known to self-assemble into various structures at the air-water interface. Specifically, polystyrene-polyethylene oxide (PS-PEO) can form large aggregates, spaghetti, or dots depending on the wt% PEO of the polymer. The polymer structures are prepared at the air water interface and transferred by Langmuir Blodgett to a silicon substrate. Linear compression on a Langmuir trough created pressure vs mean molecular area (MMA) isotherms for each blend. The deposited films from a particular MMA are imaged by Atomic Force Microscopy (AFM). Blending in the dye 1,6-diphenyl-1,3,5-hexatriene to a 34.6% PEO solution yielded larger dots with increasing frequency as the ratio of dye to polymer increased. At extremely large ratios of dye to polymer other structures such as spaghetti were produced; hence, control of the structures and their sizes is gained by addition of the dye.