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Recognition-mediated assembly of random nanoscale copolymers into ordered microscale aggregates
The non-covalent interactions that embody molecular self-assembly have developed, and continue to evolve, into a valuable instrument in the design, fabrication, and control of novel polymeric materials. To this end, we have developed a modular, ‘Plug and Play’ approach to reversible polymer side chain modification and have demonstrated this methodology to be useful for numerous applications such as solution-state control over polymer nanostructure, guest sensing, reversible surface modification, and what will be discussed throughout this thesis in particular, the formation of complex functional microstructures. Polystyrene and polynorbornene copolymers randomly dispersed with complementary thymine and diamidopyridine functionalities spontaneously assemble, in non-competitive media, into giant vesicles, or Recognition-Induced Polymersomes (RIPs) due to specific interstrand three-point hydrogen bonding. The formation of vesicular architectures from random copolymers lacking well-defined headgroups is unprecedented, providing a new method for the creation of supramolecular systems. This mode of assembly affords a new tool for the control of vesicle structure; complementary monovalent and multivalent guests distort or disrupt vesicle structure through competitive binding to the polymer recognition sites. An alternative motif to supramolecular engineering has led to the concept of noncovalent polymer crosslinking. Bis-thymine molecules were used to non-covalently crosslink a complementary diamidopyridine-functionalized copolymer. Upon combination in non-competitive solvents, discrete micron-scale spherical aggregates were formed, the size of which is controlled by crosslinker preorganization.
Thibault, Raymond J., "Recognition-mediated assembly of random nanoscale copolymers into ordered microscale aggregates" (2004). Doctoral Dissertations Available from Proquest. AAI3152752.