Paper Number
CS30                         My Program 

Session
Colloids and Suspensions

Title
Mapping structure and rheology of pH-responsive resins for low-VOC coatings

Presentation Date and Time
October 15, 2024 (Tuesday) 4:05

Track / Room
Track 2 / Waterloo 4

Authors (Click on name to view author profile)

  1. Patel, Kush J. (Northwestern University, Chemical and Biological Engineering)
  2. Bowles, Steven (PPG Industries)
  3. Matolyak, Elise (PPG Industries)
  4. Vogus, Douglas (PPG Industries)
  5. Wang, Chao (PPG Industries)
  6. Nagy, Gergely (Oak Ridge National Laboratory)
  7. Richards, Jeffrey J. (Northwestern University, Chemical and Biological Engineering)

Author and Affiliation Lines (in printed abstract book)
Kush J. Patel1, Steven Bowles2, Elise Matolyak2, Douglas Vogus2, Chao Wang2, Gergely Nagy3 and Jeffrey J. Richards1
1Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208; 2PPG Industries, Allison Park, PA 15101; 3Oak Ridge National Laboratory, Oak Ridge, TN 37830

Speaker / Presenter 
Patel, Kush J.

Keywords
colloids; emulsions; sustainability

Text of Abstract
Current formulations of many paints and coatings require high amounts of volatile organic compounds (VOCs) to achieve desired macroscopic properties. Due to growing global concern over negative environmental and human health effects, the EPA and other regulatory bodies seek to impose tighter restrictions on allowable levels of VOCs in such products. This work is in collaboration with PPG Industries who aim to develop waterborne resins consisting of water-stable core-shell (CS) polymeric colloidal particles which require lower amounts of VOCs in their formulations. The architecture of these resins has been engineered to respond to stimuli, including pH and solvent, to achieve similar rheological properties as traditional VOC solvent-borne resins. To gain a mechanistic understanding of the rheological response, we use small angle neutron scattering (SANS) to probe the microstructural response of a model CS resin to pH and solvent conditions and compare to the resin rheology. We discovered that the shell component has a unique architecture, consisting of long, polymer chains sparsely tethered to the cores. Using contrast variation SANS, we eliminate the possibility of other architectures by comparing to a resin consisting of only the core component. From this discovery, we approximate the viscosity of the resin as a linear combination of the contributions from the core and shell. We can then identify the responsive nature of the shell component and provide predictive insight to the rheology.