Small-Angle Neutron Scattering Analysis of Bottlebrush Backbone and Side-Chain Flexibility
Stacy Lee Pesek, Qiqi Xiang, Boualem Hammouda, Rafael Verduzco
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 N0.55 while the overall bottlebrush increases in size proportional to N0.77. These results demonstrate that the bottlebrush backbone is not fully extended and has significant conformational flexibility in solution.
, Xiang, Q.
, Hammouda, B.
and Verduzco, R.
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 November 29, 2023)