| Sum frequency generation (SFG) has been used to study anti-fouling polymers with the goal of understanding their surface properties. SFG has been used to examine several diblock pyridinium based polymers and a tri-block amphiphilic polymer. For the case of the pyridinium based polymers, it was found that the presence of a fluorinated side chain results in different behavior when interacting with a lipid bilayer, a model system for cell membranes. Varying the geometry was found to result in significant changes in the SFG spectrum acquired. This resulted in the decision to run thickness dependent experiments on the tri-block amphiphilic polymer.;It was observed that in both air and D2O that the generated SFG signal from the amphiphilic polymer was dependent on thickness. In order to further characterize this behavior, examination of the Fresnel coefficients for both environments was explored. Results indicated that the polymer/air(D 2O) interfaces dominates, but that there is destructive interference from the buried polymer/substrate interface. Alkyl side chains were also observed to undergo an orientation change between the two environments. However, the fluorinated segments can be found at the interface in both environments.;To better understand the assignment for the signal from the fluorinated segments, a partially fluorinated silane was used to create a self assembled monolayer for use as a reference. It is believed that the assignment to the asymmetric stretching mode of the terminal CF3 group is the most accurate assignment. Lastly, a method to examine the orientation of para-substituted phenyl rings was developed so that further understanding of the pyridinium rings might be achieved. Using sulfonated polystyrene, it was found that for para-substituted phenyl rings, the assumption of isotropic twist may not be accurate. |
