ORGS1-1047
Hydrolysis-Activated Bottlebrush Polymer Surfactants with Architecture-Dependent Interfacial Activity
Topic
GS1. Graduate Student Oral Session I: Colloidal and Interfacial Polymer Science
When and Where
Sep 28, 2026
16:48 - 17:00
Room 101
Session Chairs
Yoon-Ho HWANG
Jang-Hwan KIM
Hyosung AN
Presenter(s)
Kyoungwon Lee (University of Massachusetts Amherst)
Co-Author(s)
Abstract
Acid-responsive bottlebrush random copolymers (BRCPs) bearing solketal-substituted and unsubstituted polystyrene side chains were synthesized via graft-through ring-opening metathesis polymerization. At the water/oil interface, exposure to acidic aqueous conditions induced in situ hydrolysis of hydrophobic solketal groups into 1,2-diols, transforming the BRCPs into amphiphilic macromolecular surfactants. Time-resolved pendant-drop tensiometry revealed two relaxation regimes corresponding to interfacial adsorption and hydrolysis-driven reorganization. Hydrolysis followed first-order kinetics with apparent rate constants of approximately 0.06–0.14 h⁻¹; longer backbones accelerated hydrolysis, while higher grafting densities slowed interfacial reorganization due to steric constraints. Upon acid exposure, the interfacial tension decreased from approximately 25 to 10 mN m⁻¹, and spontaneous emulsification was observed in short-backbone, densely grafted BRCPs. These results demonstrate how bottlebrush architecture and grafting density govern dynamic interfacial responsiveness, providing design rules for stimuli-triggered emulsification and adaptive soft materials.
