Effect of Polymer Composition and Morphology on Mechanochemical Activation in Nanostructured Triblock Copolymers.

Autor:	Huo Z; Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States., Arora S; Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States., Kong VA; Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States., Myrga BJ; Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States., Statt A; Materials Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana-Champaign, Illinois 61801, United States., Laaser JE; Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States.
Jazyk:	angličtina
Zdroj:	Macromolecules [Macromolecules] 2023 Mar 02; Vol. 56 (5), pp. 1845-1854. Date of Electronic Publication: 2023 Mar 02 (Print Publication: 2023).
DOI:	10.1021/acs.macromol.2c02475
Abstrakt:	The effect of composition and morphology on mechanochemical activation in nanostructured block copolymers was investigated in a series of poly(methyl methacrylate)- block -poly( n -butyl acrylate)- block -poly(methyl methacrylate) (PMMA- b -PnBA- b -PMMA) triblock copolymers containing a force-responsive spiropyran unit in the center of the rubbery PnBA midblock. Triblock copolymers with identical PnBA midblocks and varying lengths of PMMA end-blocks were synthesized from a spiropyran-containing macroinitiatior via atom transfer radical polymerization, yielding polymers with volume fractions of PMMA ranging from 0.21 to 0.50. Characterization by transmission electron microscopy revealed that the polymers self-assembled into spherical and cylindrical nanostructures. Simultaneous tensile tests and optical measurements revealed that mechanochemical activation is strongly correlated to the chemical composition and morphologies of the triblock copolymers. As the glassy (PMMA) block content is increased, the overall activation increases, and the onset of activation occurs at lower strain but higher stress, which agrees with predictions from our previous computational work. These results suggest that the self-assembly of nanostructured morphologies can play an important role in controlling mechanochemical activation in polymeric materials and provide insights into how polymer composition and morphology impact molecular-scale force distributions. Competing Interests: The authors declare no competing financial interest. (© 2023 The Authors. Published by American Chemical Society.)
Databáze:	MEDLINE
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