University of Illinois Urbana-Champaign

Understanding molecular aspects of mass transport in charged and uncharged dense polymer networks

Sheridan, Grant S.

Content Files
SHERIDAN-DISSERTATION-2022.pdf

Permalink

https://hdl.handle.net/2142/115466

Description

Title
Understanding molecular aspects of mass transport in charged and uncharged dense polymer networks
Author(s)
Sheridan, Grant S.
Issue Date
2022-04-21
Director of Research (if dissertation) or Advisor (if thesis)
Evans, Christopher M
Doctoral Committee Chair(s)
Evans, Christopher M
Committee Member(s)
  • Schweizer, Kenneth S
  • Braun, Paul V
  • Sing, Charles E
Department of Study
Materials Science & Engineerng
Discipline
Materials Science & Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • polymer
  • polymer physics
  • diffusion
Abstract
Polymer membranes are the future of separation, providing an energy efficient means of separation. Glassy polymer membranes have typically held the advantage over rubbery polymer membranes due to their higher selectivity; however, the work of this thesis aims to develop a molecular understanding of mass transport in dense rubbery polymer membranes to inspire the next generation of rubbery polymer membranes that can separate compounds based on size exclusion, combining the high permeability of rubbery polymer membranes with the high selectivity of glassy polymers. Imidazolium ionic liquid membranes were developed with varying ionic liquid moiety and crosslink density for the separation of toluene and heptane. TFSI- ionic liquid moieties showed improved toluene-heptane separation performance over their BF4- counterparts. Decreasing the crosslink density of the TFSI- polymerized ionic liquid membranes also led to a non-monotonic trend in permselectivity. The effect of crosslink density on mass transport was further investigated via probe diffusion in butyl acrylate polymer networks, where crosslinking significantly increased the glass transition temperature, reduced segmental dynamics, and reduced probe diffusion. Probe diffusion compared to segmental relaxation times revealed diffusion partially decoupled from segmental dynamics, where varying probe size led to a difference in diffusivity that could be accounted for by the inscribed probe volume. These results provide new insights regarding the effect of covalent crosslinks on probe diffusion necessary for the design and development of separation membranes.
Graduation Semester
2022-05
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/115466
Copyright and License Information
Copyright 2022 Grant Sheridan

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois