Small-Angle Neutron Scattering Analysis of Bottlebrush Backbone and Side-Chain Flexibility

Published

May 1, 2017

Author(s)

Stacy Lee Pesek, Qiqi Xiang, Boualem Hammouda, Rafael Verduzco

Abstract

Bottlebrush polymers have densely tethered side-chains that are grafted to a linear polymer backbone, resulting in stretching of both the side-chains and backbone. Prior studies have reported that the side-chains are only weakly stretched while the backbone is highly elongated. Here, scaling laws for the bottlebrush backbone and side-chains are derived through small-angle neutron scattering analysis of a systematic series of poly(lactic acid) (PLA) bottlebrush polymers synthesized via a "grafting-through" ring-opening polymerization. Scattering profiles are modeled with the empirical Guinier-Porod, rigid cylinder, and flexible cylinder models. Side chains are found to be only weakly stretched, with an end-to-end distance proportional to N^0.55 while the overall bottlebrush increases in size proportional to N^0.77. These results demonstrate that the bottlebrush backbone is not fully extended and has significant conformational flexibility in solution.

Citation

Journal of Polymer Science Part B-Polymer Physics

Volume

55

Issue

1

Pub Type

Journals

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Keywords

Bottlebrush polymers, side-chain, backbone, SANS, small-angle

Citation

Pesek, S. , Xiang, Q. , Hammouda, B. and Verduzco, R. (2017), Small-Angle Neutron Scattering Analysis of Bottlebrush Backbone and Side-Chain Flexibility, Journal of Polymer Science Part B-Polymer Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921353 (Accessed April 25, 2024)