Paper Number
SM41 

Session
Polymers Solutions, Melts, and Blends

Title
Retaining structural color in a diblock bottlebrush copolymer solution

Presentation Date and Time
October 13, 2021 (Wednesday) 5:00

Track / Room
Track 1 / Ballroom 5

Authors (Click on name to view author profile)

  1. Wade, Matthew A. (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)
  2. Kamble, Yash (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)
  3. Walsh, Dylan (Massachusetts Institute of Technology, Chemical Engineering)
  4. Guironnet, Damien (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)
  5. Rogers, Simon A. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Matthew A. Wade1, Yash Kamble1, Dylan Walsh2, Damien Guironnet1 and Simon A. Rogers1
1Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801; 2Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142

Speaker / Presenter 
Wade, Matthew A.

Keywords
additive manufacturing; applied rheology; flow-induced instabilities; gels; polymer blends; polymer solutions

Text of Abstract
Building upon previously established structure-property-property relations between the self-assembled microstructure of a diblock bottlebrush polymer solution, its color, and the applied shear conditions, two avenues for retaining the induced structure over longer periods of time are explored. In-situ UV curing was carried out on a functionalized polylactic acid-b-polystyrene bottlebrush copolymer and dispersed in toluene at 5 °C forming a solution with a concentration of 175 mg/ml. Photo initiator and a thiol were added to the solution to promote crosslinking between functionalized polymers when exposed to UV radiation. The dynamics of this curing process were characterized with both traditional techniques and the SPP framework. The timeframe for forming a percolated network was found to be on the order of a couple of seconds when exposed to UV intensities between 300 and 950 mW/cm2. As an alternative to UV curing, a diblock bottlebrush solution with a concentration of 350 mg/ml was explored. This solution was found to exhibit yield-like behavior. Using oscillatory recovery rheology, the moduli were decomposed into recoverable and unrecoverable components. By defining a time resolved Deborah number, we can identify when the material begins to exhibit more solid-like and more liquid-like behavior. Structural characterization will be carried out to identify the structural changes that correspond to the liquid to solid transition. The two approaches we present can be used to potentially retain the structures induced through shear.