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ABSTRACT The phase behavior of [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blends with amorphous polymers with different degrees of aromaticity has been investigated by differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). The polymers investigated are the homologous series of polystyrene (PS), poly(2-vinyl-naphthalene) (P2VN), and poly(9-vinyl-phenanthrene) (P9VPh). The DSC results show that the miscibility of PCBM in these polymers increases nonlinearly from 16.5 wt % in PS, 57.0 wt % in P2VN, and 74.9 wt % in P9VPh. The SANS results show that at all concentrations of PCBM, the blends are composed of two mixed phases. Analysis shows that the phase dimensions remain largely independent of PCBM content, but there is a strong dependence of the PCBM concentration difference in the two phases with increasing PCBM content. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 994-1001 [ABSTRACT FROM AUTHOR]

Nanoscale bulk heterojunction (BHJ) systems, consisting of fullerenes dispersed in conjugated polymers have been actively studied in order to produce high performance organic photovoltaics. How the BHJ morphology affects device efficiency, is currently ill-understood. Neutron reflection together with grazing incidence X-ray and neutron scattering and X-ray photoelectron spectroscopy are utilized to gain understanding of the BHJ morphology in functional devices. For nine model systems, based on mixtures of three poly(3-alkyl thiophenes, P3AT) (A = butyl, hexyl, octyl) blended with three different fullerene derivatives, the BHJ morphology through the film thickness is determined. It is shown that fullerene enrichment occurs at both the electrode interfaces after annealing. The degree of fullerene enrichment is found to strongly correlate with the short circuit current ( JSC ) and to a lesser degree with the fill factor. Based on these findings, it is demonstrated that by deliberately adding a fullerene layer at the electron transport layer interface, JSC can be increased by up to 20%, resulting in an overall increase in power conversion efficiency of 5%. [ABSTRACT FROM AUTHOR]

A unique in situ multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) measurements. SAXS and WAXS patterns of high-density polyethylene (HDPE) and HDPE/clay nanocomposites were measured in real time during in situ multiaxial deformation at room temperature and at 55 °C. It was observed that the morphological evolution of polyethylene is affected by the existence of clay platelets as well as the deformation temperature and strain rate. Martensitic transformation of orthorhombic into monoclinic crystal phases was observed under strain in HDPE, which is delayed and hindered in the presence of clay nanoplatelets. From the SAXS measurements, it was observed that the thickness of the interlamellar amorphous region increased with increasing strain, which is due to elongation of the amorphous chains. The increase in amorphous layer thickness is slightly higher for the nanocomposites compared to the neat polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 [ABSTRACT FROM AUTHOR]

Linear triblock terpolymers of poly( n-butyl methacrylate)- b-poly(methyl methacrylate)- b-poly(2-fluoroethyl methacrylate) (PnBMA-PMMA-P2FEMA) were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization. Kinetic studies of the homopolymerization of 2FEMA by RAFT polymerization demonstrated controllable characteristics with fairly narrow polydispersities (∼1.30). The resultant PnBMA-PMMA-P2FEMA triblock terpolymers were characterized via 1H NMR, 19F NMR, and gel permeation chromatography. These polymers formed micellar aggregates in a selective solvent mixture. The as-formed micelles were analyzed using scanning electron microscopy and dynamic light scattering. It was found that these terpolymers could directly self-organize into complex micelles in a tetrahydrofuran/methanol mixture with diameters that depended on polymer composition. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

The article discusses a study on drop impaction on surfaces. In the study, impaction on smooth solid substrates of drops formed by the drop-on-demand (DOD) inkjet printing method was investigated over a wide range of impaction speeds. Drops were generated using a piezoelectric actuated inkjet printhead and millimeter-scale drops were generated using a dripping method. Glass slides, thermal oxidized silicon wafer, and three self-assembled monolayers (SAMs) on gold coated silicon wafers were used as substrates for drop impaction.