International Research Experience for Undergraduates

Jessica Hancock

2002 Participant

Hancock

The Synthesis and Characterization of Amphiphilic Copolymers of Poly(chloromethylstyrene)-b-polystyrene

Amphiphilic polymers are used to control the rheology of aqueous formations and the colloidal stability of emulsions or polymer suspensions. My research will analyze properties of two amphiphilic copolymers of poly(chloromethylstyrene)-b-styrene, with varying molar ratios, to evaluate the polymers self-organization capacity in water.

The desired copolymers, poly(chloromethylstyrene)-b-styrene, will be synthesized using controlled free-radical polymerization. This technique includes the presence of mediating radicals which produce reversible termination of the propagating radicals. This property drastically reduces the concentration of reactive chain ends, thus minimizing unwanted irreversible termination reactions, including combination or disproportionation. There are several characteristics of controlled free-radical polymerization, including linear relationships between ln(1-conversion) vs. time, Mn vs. time, and a low polydispersity. Therefore, the confirmation of a controlled free-radical reaction can be obtained by monitoring the kinetics of each polymerization. For my research, all polymerizations will be mediated by the nitroxide, TEMPO and initiated with AIBN. The first and second copolymer will be synthesized to possess within 10,000-20,000Mn and contain 45/55 and 30/70 molar ratios, respectively.

Following successful polymerizations of poly(chloromethylstyrene)-b-styrene, the copolymers will be quaternized with N,N-dimethyldodecylamine. Ideally, once quaternized, solubility in water will be achieved. The behavior exhibited by each new amphiphilic copolymer, in the presence of water, will then be studied and compared, including viscosity and self-assembly patterns.