Controlling effective interactions and spatial dispersion of nanoparticles in multiblock copolymer melts

Journal Article · Thu Jun 04 04:00:00 EDT 2015 · Journal of Polymer Science. Part B, Polymer Physics

DOI:https://doi.org/10.1002/polb.23752· OSTI ID:1265585

Banerjee, Debapriya ^[1]; Schweizer, Kenneth S. ^[1]

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1. Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Frederick Seitz Materials Research Lab.

The microscopic Polymer Reference Interaction Site Model theory is employed to study, for the first time, the effective interactions, spatial organization, and miscibility of dilute spherical nanoparticles in non-microphase separating, chemically heterogeneous, compositionally symmetric AB multiblock copolymer melts of varying monomer sequence or architecture. The dependence of nanoparticle wettability on copolymer sequence and chemistry results in interparticle potentials-of-mean force that are qualitatively different from homopolymers. An important prediction is the ability to improve nanoparticle dispersion via judicious choice of block length and monomer adsorption-strengths which control both local surface segregation and chain connectivity induced packing constraints and frustration. The degree of dispersion also depends strongly on nanoparticle diameter relative to the block contour length. Small particles in copolymers with longer block lengths experience a more homopolymer-like environment which renders them relatively insensitive to copolymer chemical heterogeneity and hinders dispersion. Larger particles (sufficiently larger than the monomer diameter) in copolymers of relatively short block lengths provide better dispersion than either a homopolymer or random copolymer. The theory also predicts a novel widening of the miscibility window for large particles upon increasing the overall molecular weight of copolymers composed of relatively long blocks. The influence of a positive chi-parameter in the pure copolymer melt is briefly studied. Quantitative application to fullerenes in specific copolymers of experimental interest is performed, and miscibility predictions are made.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1265585
• Journal Information: Journal of Polymer Science. Part B, Polymer Physics, Journal Name: Journal of Polymer Science. Part B, Polymer Physics Journal Issue: 16 Vol. 53; ISSN 0887-6266
• Publisher: Wiley
• Country of Publication: United States
• Language: English

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