Publication

Shape-Persistent, Thermoresponsive Polypeptide Brushes Prepared by Vapor Deposition Surface-Initiated Ring-Opening Polymerization of alpha-Amino Acid N-Carboxyanhydrides

Abstract

Surface-grafting thermoresponsive polymers allows the preparation of thin polymer brush coatings with surface properties that can be manipulated by variation of temperature. In most instances, thermoresponsive polymer brushes are produced using polymers that dehydrate and collapse above a certain temperature. This report presents the preparation and properties of polymer brushes that show thermoresponsive surface properties, yet are shape-persistent in that they do not undergo main chain collapse. The polymer brushes presented here are obtained via vapor deposition surface-initiated ring-opening polymerization (SI-ROP) of gamma-di- or tri(ethylene glycol)-modified glutamic acid N-carboxyanhydrides. Vapor deposition SI-ROP of gamma-di- or tri(ethylene glycol)-modified l- or d-glutamic acid N-carboxyanhydrides affords helical surface-tethered polymer chains that do not show any changes in secondary structure between 10 and 70 degrees C. QCM-D experiments, however, revealed significant dehydration of poly(gamma-(2-(2-methoxyethoxy)ethyl)-l-glutamate) (poly(L-EG(2)-Glu)) brushes upon heating from 10 to 40 degrees C. At the same time, AFM and ellipsometry studies did not reveal significant variations in film thickness over this temperature range, which is consistent with the shape-persistent nature of these polypeptide brushes and indicates that the thermoresponsiveness of the films is primarily due to hydration and dehydration of the oligo(ethylene glycol) side chains. The results presented here illustrate the potential of surface-initiated NCA ring-opening polymerization to generate densely grafted assemblies of polymer chains that possess well-defined secondary structures and tunable surface properties. These polypeptide brushes complement their conformationally unordered counterparts that can be generated via surface-initiated polymerization of vinyl-type monomers and represent another step forward to biomimetic surfaces and interfaces.

About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chatbot

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.