| Theoretical studies were conducted to elucidate the interplay between polymeric materials and external fields. External fields had a broad sense in this dissertation, including applied electric fields, confining boundaries, and medium induced potentials. Several polymer models have been investigated to understand field induced conformational deformation for flexible chains, orientation ordering for rigid rods, and aggregate formation in the presence of polymers. The essence of this research was to explore the effects of the local architecture of different polymer models on the static polymer properties. In each project, the local structure of a chosen model was modified to different extent, and the properties predicted by each level of model were investigated.; It was first shown that modification of a small portion of polymer molecules slightly deformed chain conformation, but would not affect the fundamental physics behind their conformational behavior. Such a result has been observed when the external field was weak or absent. When the strength of applied potentials (electric fields and confining potentials) was increased, the local polymer structure became more important because the effect of intrinsic monomer characteristics associated with the monomer chemical architecture was amplified. As two models were compared, the dividing line to separate the regimes of weak and strong fields could be defined at the field strengths where the local polymer structure starts to influence their polymer properties. Also, the results illustrated the general trend regarding how the local structure of polymers should be altered to maximize their response to external fields. These findings will facilitate the future development of applications and the design of more useful materials. Furthermore, aggregation of smaller particles in templated polymers was investigated. The chain connectivity prevented complex formation between the dispersed particles and polymers when their interactions were effectively attractive. As a result, the probability of forming larger aggregates increased. At the practical standpoint, these studies provided the insight into mechanisms for polymer mediated nanoparticle formation, which has been widely employed to manufacture nanoparticles of different geometry and size. |
