We are studying the assembly of bottlebrush random copolymers (BRCPs) at fluid interfaces. BRCPs containing hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(dimethylsiloxane) (PDMS) as the sidechains were prepared by ring-opening metathesis polymerization (ROMP) using ruthenium benzylidene catalysis. The results showed a strong relationship between the molecular weight of the polymer and the interfacial assembly kinetics. The relaxation behavior (associated with the interfacial tension drop) of the polymers at the water-toluene interface was investigated further by fitting the interfacial tension vs time plot with the sum of two exponential decay functions to extract the key characteristic relaxation times described as reconfiguration and reorganization. The results showed that with increasing molecular weight the relaxation time for BRCP reconfiguration and adsorption to the fluid-fluid interface increased, while the relaxation time related to reconfiguration of the polymers decreased. The time-dependent relaxation behavior and the collective diffusion coefficient were further investigated by fluorescence recovery after photobleaching. These findings provide both a new fundamental understanding of the interplay between polymer molecular weight and their assembly behavior at fluid interfaces, and the generalized design rules for bottlebrush random copolymers as emulsifiers.

Unique properties of bottlebrush polymers at fluid interfaces

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.