Complex polymer micelles in solutions and on surfaces

Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) was synthesized by anionic polymerization. Micellization of (PS-b-P2VP) was accomplished by dissolving the polymer in a 45:50:5 volume ratio methanol:dioxane:water mixture followed by a stepwise dialysis into a 0.1 M HCl solution. The hydrophobic PS blocks form the core of the micelles, and the protonated P2VPH+ forms the outer shell. Addition of poly(2-vinylpyridine)-block-polyethyleneoxide (P2VP-b-PEO) and titration to a pH above 10 causes a coprecipitation of the P2VP blocks of both copolymers, forming three-layered micelles that we refer to as "onion" micelles. The micellar structures were investigated by static and dynamic light scattering and transmission electron microscopy. The weight ratio of P2VP-b-PEO to PS-bP2VP was varied during the onion micelle preparation to study the fraction of P2VP-b-PEO that is adsorbed on the PS-b-P2VP "core micelle". The stability with respect to dilution of the micelles formed from PS-b-P2VP and of the onion micelles was studied.;The interaction of poly(styrenesulfonate) (PSS) with PS-b-P2VP micelles was investigated. The charge neutralization of P2VPH+ by PSS - may result precipitation. However, when present in excess PSS- may keep the complex particle in solution. It is expected that PS forms the core of the particle, the P2VPH+-PSS - comprises the next layer, and the excess PSS- forms the outermost layer. The three-layered complex assembly of polyelectrolytes may also be considered an "onion-type" micelle. The structure and properties of these "onions" are investigated using light scattering and SEM images of the negatively charged onion micelles attached to positively charged surfaces.;Modifications of various surfaces with polymer micelles were performed. The acid micelles were attached to modified quartz, untreated gold and silicon wafer surfaces. Modified quartz surfaces were prepared by altering its surface functional group from hydroxyls to amines. The surfaces were acidified to protonate the amines and form the positive charges. Polystyrene sulfonate attached to the surfaces changes the surface charges to negative. The cationic polymer micelles are then adsorbed onto the anionic sulfonated layer. Electrostatic attraction should be the primary driving force for these polyelectrolyte and micelle attachments. Analogous surface modifications on untreated gold and silicon wafer with acid micelles were made, but in this case the origin of the micelle-surface attraction is not so obvious.