Paper Number
VP33 

Session
Pre-recorded Flash Presentations (virtual)

Title
Understanding the morphology and self-stratification in multiphase polymer colloidal films

Presentation Date and Time
All Week (Asynchronous) Any Time

Track / Room
Pre-recorded Presentation / Virtual

Authors (Click on name to view author profile)

  1. Singh, Piyush K. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
  2. Pacholski, Michaeleen L. (The Dow Chemical Company)
  3. Gu, Junsi (The Dow Chemical Company)
  4. Singhal, Gaurav (University of Illinois at Urbana-Champaign, Department of Materials Science and Engineering)
  5. Go, Yookyung (University of Illinois at Urbana-Champaign, Department of Materials Science and Engineering)
  6. Leal, Cecilia (University of Illinois at Urbana-Champaign, Department of Materials Science and Engineering)
  7. Braun, Paul V. (University of Illinois at Urbana-Champaign, Department of Materials Science and Engineering)
  8. Patankar, Kshitish (The Dow Chemical Company)
  9. Drumright, Ray (The Dow Chemical Company)
  10. Rogers, Simon A. (University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
  11. Schroeder, Charles M. (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Piyush K. Singh1, Michaeleen L. Pacholski2, Junsi Gu2, Gaurav Singhal3, Yookyung Go3, Cecilia Leal3, Paul V. Braun3, Kshitish Patankar4, Ray Drumright4, Simon A. Rogers1 and Charles M. Schroeder3
1Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; 2The Dow Chemical Company, Collegeville, PA; 3Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; 4The Dow Chemical Company, Midland, MI

Speaker / Presenter 
Singh, Piyush K.

Keywords
colloids; composites; polymer blends; polymer melts

Text of Abstract
Latexes (polymer colloids) are frequently used in household paints and varnishes, pressure-sensitive adhesives, textile and carpet backings, paper coatings, inks and gloves etc. While the structure and morphology evolution of a homogenous latex film is well understood, polymer nanocomposite films made from, for example, mixture of latexes or multiphase latexes are still a topic of intensive research. In this work, we study composite latexes to optimize them for self-stratified films, which provide strong adhesion with the substrate and water repellency (or any other desired property) at the air-film interface simultaneously. We tested two multiphase latexes, both comprising of a weakly entangled acrylic component and a strongly entangled acrylic-silicone copolymer, but having different particle morphologies: blend-like mixture of two latexes, and core-shell morphology with acrylic-silicone cores. A confident assessment of the morphology of composite films and the underlying mechanisms required complementary data from different techniques at various stages of drying: Cryo-TEM, rheology, microscopy, SIMS, SAXS and XPS etc. We observe that the morphology of a multiphase latex film is kinetically controlled, and at room temperature (~ Tg +14°C) the large Mw acrylic-silicone cores are embedded in the lower Mw acrylic matrix for both latexes. However, drying at elevated temperatures (~Tg +60°C) results in very distinct morphologies for the two systems. While the core-shell system remains unchanged with heat ageing, the blend-like system results in coalescence of acrylic-silicone domains within the acrylic matrix although an ideal self-stratification with two distinct layers is not observed. Future directions include studying multiphase latexes with both phases comprising of unentangled polymers, and with larger surface energy difference between them. Our work provides a robust toolbox and strategies for studying complex latexes, and fundamental insights into the development of new smart coating formulations.