Paper Number
PO30 

Session
Poster Session

Title
Color, rheology, and microstructure of bottlebrush diblock copolymer solutions

Presentation Date and Time
October 23, 2019 (Wednesday) 6:30

Track / Room
Poster Session / Ballroom C on 4th floor

Authors (Click on name to view author profile)

  1. Wade, Matthew A. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
  2. Lee, Johnny Ching-Wei (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)
  3. Kelley, Elizabeth (NIST)
  4. Weigandt, Katie M. (NIST Center for Neutron Research)
  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, Johnny Ching-Wei Lee1, Elizabeth Kelley2, Katie M. Weigandt3, and Simon A. Rogers1
1Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; 2NIST, Gaithersburg, MD; 3NIST Center for Neutron Research, Gaithersburg, MD 20877

Speaker / Presenter 
Wade, Matthew A.

Text of Abstract
The formation of structure-property-processing relations is crucial to designing energy-efficient processes and defect-free products. We present the results of a comprehensive study that combines data from imaging, rheometry, and scattering techniques to holistically describe the color, rheology, and microstructure of a solution of bottlebrush diblock copolymers under steady shearing conditions. Studies were carried out on a 16.8 wt% solution of poly(norbornene-g-poly(lactic acid)60)200-b-poly(norbornene-g-poly(styrene)45)200 polymers suspended in toluene. Rheo-small angle neutron scattering (rheo-SANS) measurements were performed in the velocity-vorticity (1-3) and velocity gradient-vorticity (2-3) planes over shear rates ranging from 0 to 100 s-1. The resulting scattering patterns indicate the presence of lamellar stacking along the velocity gradient direction under quiescence and low shear conditions (0.01 s-1), distortions of the lamellae at intermediate shear rates, and the formation of leek-like structures along the velocity direction at high shear rates. These changes in microstructure closely mirror the striking changes in sample color with shear in which the sample appears green under quiescent and low shear conditions and transitions to teal and blue at higher shear rates. The correlation between sample color, microstructure, and rheology presented here lays the groundwork for understanding the complex interplay between structure and function that dictates the success of additive manufacturing using bottlebrush diblock copolymers.