Date of Award

2018

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

Sub-Department

College of Arts and Sciences

First Advisor

Morgan Stefik

Abstract

The controlled fabrications of porous materials are crucial for a wide variety of uses spanning the gamut from energy applications to filtration. Despite decades of developments based upon block copolymer self-assembly there remain numerous limitations to achieve simple ends such as fully-tunable nanomaterials or well-defined macroscopic forms. For example, fundamental studies of nanostructure-performance relationships need systematic series of nanomaterials to identify the separate effects of wall and pore dimensions. Such precision control is impossible under the constraints of equilibrating systems. Persistent Micelle Templating (PMT) is rather based on kinetic control and enables robust and independent tuning of each feature. However, PMT development has been slow, requiring tedious polymerizations and extensive solution optimizations. These challenges were resolved with complete synthesis and templating within 24 hours combined with an efficient one-pot PMT titration approach supported by rapid SAXS modeling. Remarkable precision tuning was demonstrated with ~2 Å feature size increment. The PMT demonstrations to date were over a limited size range where these new developments enabled confirmation that tuning of solvent thermodynamics enables expanded PMT control will the smallest ~13 nm pore sizes. Turning towards enabling much larger feature sizes, an approach based upon homopolymer swelling of micelles showed a markedly enhanced tunability of pore size while preserving kinetic control. Lastly, producing such well-defined porous material in macroscopic forms has remained elusive. A faster and more selective etching chemistry was developed for polylactide based block copolymers to preserve pristine nanostructure preservation without detectable matrix degradation for up to 2 mm thick monolithic films. This body of work expands both the scope and control of porous materials derived from polymers with implications to numerous applications.

Rights

© 2018, Amrita Sarkar

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