Specific ion effects on transient polymers: a new strategy for programmable microcapusles

Transient polymers are emerging materials that transform from macromolecules to small molecules triggered by predefined environmental stimuli. Distinct from traditional degradable polymers, transient materials undergo domino like chain unzipping reactions, leading to controlled and complete depolymerization upon one cleavage. Taking advantage of the unique feature of triggered materials transience, this dissertation focuses on developing transient polymer microcapsules for programmable payload release. In Chapter 2, a rapid solvent evaporation strategy was developed to prepare transient polymer microcapsules with a low-ceiling-temperature polymer, cyclic poly(phthalaldehyde) (cPPA), as the shell wall materials. Chapter 3 described an ion co-activation effect that modulated cPPA depolymerization rates in the presence of acid. In Chapter 4, we further investigated the ion specificity in the co-activation effect and anion solvation properties were found to significantly impact the co-activation behavior. Based on the specific ion co-activation effect, we developed programmable microcapsules whose payload release kinetics depends on the ionic species in the solutions. Chapter 5 further expanded the co-activation effect in Lewis acid solutions that achieved depolymerization in mild environment. In Chapter 6, several studies were devoted to understand the molecular and interfacial mechanisms of the ion co-activation effect. Chapter 7 reviewed current topics on the Hofmeister effect and constructed a crude model on auto-catalytic microcapsules. The thesis research offers an encapsulation strategy and ion library for triggered release microcapsules and will be of significance for designing logic gate responsive microcapsules, reversible activation-deactivation materials and self-regulating reaction networks in autonomous chemical system.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Tang, Shijia

Contributors dc:contributor

• Moore, Jeffrey S.
• Braun, Paul V.
• Chen, Qian
• Evans, Christopher M.

• Transient polymers, Triggered release, Hofmeister effect, Depolymerization kinetics

Statement dc:rights

• Copyright 2018 Shijia Tang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/101693

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/101693