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Block copolymers (BCPs) have received significant attention as promising candidates for sequestering nanoparticles and fabrication of aligned nanostructures with optimal optical or electrical properties. We investigate the influence of static and dynamic thermal field on the alignment of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) BCP morphology with the loading of novel poly(methyl methacrylate‐block‐Polystyrene) (PMMA‐b‐PS)‐grafted‐TiO2 nanoparticles (BCP‐g‐TiO2). Observation of characteristics IR peaks for PMMA and PS in BCP‐g‐TiO2 nanoparticles and Transmission Electron Microscopy (TEM) results of the outer coating of core nanoparticle, validate the grafting to approach in synthesizing BCP‐g‐TiO2. Here we report that under the sharp dynamic thermal field, at low loading of BCP‐g‐TiO2, there is good dispersion of nanoparticles in unidirectionally aligned BCP matrix in film interior probed by GISAXS, while, at high nanoparticle loading (~10 wt%), there is local frustration in the unidirectional alignment of the BCP matrix due to aggregation of BCP‐g‐TiO2 nanoparticles. However, Grazing incidence small angle X‐ray scattering (GISAXS) shows clearly that the BCP films remain largely locally ordered at the domain scale, despite these large perturbations to long‐range ordering even at high loading level, while bringing in new TiO2 functionality to the BCP films, such as UVO absorptivity or biofouling prevention, important to potential new applications of such membranes. [ABSTRACT FROM AUTHOR]

ABSTRACT Nanoparticles provide an attractive route to modifying polymer thin film properties, yet controlling the dispersion and morphology of functionalized nanoparticle filled films is often difficult. Block copolymers can provide an ideal template for directed assembly of nanoparticles under controlled nanoparticle-polymer interactions. Previously we observed that neat films of cylinder forming poly(styrene-b-methyl methacrylate) PS-b-PMMA block copolymer (c-BCP) orient vertically with dynamic sharp thermal cold zone annealing (CZA-S) over wide range of CZA-S speed (0.1-10) μm/s. Here, we introduce a low concentration (1-5 wt %) of nanoparticles of phenolic group functionalized CdS (fCdS-NP), to PMMA cylinder forming polystyrene- b-poly (methyl methacrylate) block copolymer (c-BCP) films. Addition of the fCdS-NP induces a vertical to horizontal orientation transition at low CZA-S speed, V = 5 μm/s. The orientation flip studies were analyzed using AFM and GISAXS. These results confirm generality of our previously observed orientation transition in c-BCP under low speed CZA-S with other nanoparticles (gold [Au-NP], fulleropyrrolidine [NCPF-NP]) in the same concentration range, but reveal new aspects not previously examined: (1) A novel observation of significant vertical order recovery from 5-10% vertical cylindrical fraction at V = 5 μm/s to 46-63% vertical cylindrical fraction occurring at high CZA-S speed, V = 10 μm/s for the fCdS nanoparticle filled films. (2) We rule out the possibility that a nanoparticle wetting layer on the substrate is responsible for the vertical to horizontal flipping transition. (3) We demonstrate that the orientation flipping results can be achieved in a nanoparticle block copolymer system where the nanoparticles are apparently better-dispersed within only one (matrix PS) domain unlike our previous nanoparticle system studied. We consider facile processing conditions to fabricate functionalized nanoparticles filled PS-PMMA block copolymer films with controlled anisotropy, a useful strategy in the design of next generation electronic and photonic materials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 604-614 [ABSTRACT FROM AUTHOR]

ABSTRACT The objective of the study is to formulate exclusive block copolymer (BCP) nanocomposites by dispersing bcp end-grafted nanoparticles (bcp- g-nps) of PMMA- b-PS- g-TiO2 within PS- b-PMMA matrix. PMMA- b-PS- g-TiO2 is synthesized using a 'grafting-to' approach and characterized by XPS and TGA to establish that the copolymer chains were bonded to NPs. Good dispersion of bcp- g-nps in PMMA and PS-PMMA bcp films is observed, in contrast to poor dispersion in PS films. In PS-PMMA films, the compatible and identical bcp nature of the end-grafted polymer, and large NP size caused it to span across entire PS-PMMA domains. Poor and good dispersion in PS and PMMA matrices, respectively, can be rationalized by the fact that NPs interactions are driven by the PMMA at the outer corona of the bcp- g-nps. Developing bcp- g-nps as a strategic route to preparation of highly dispersed high permittivity NPs like titanium dioxide (TiO2) in bcp matrix can have important ramifications for energy storage devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 468-478 [ABSTRACT FROM AUTHOR]