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Conjugated polymers doped with fullerenes have shown promising application in photovoltaic cells, in which photoinduced charge transfer takes place. Here, we report a novel composite that was prepared by in situ polymerization of s-conjugated hyperbranched polysilane in the presence of fullerene. Both of the hyperbranched polysilane and fullerene have 3D structures, which are propitious to preparing materials with interpenetrating structure. The resulting composite has good solubility in common organic solvents and the UV spectrum edge suggests a low bandgap. Photoluminescence quenching in the composite is shown by the PL spectra and is also observed from the fluorescence microscopy images, which may be ascribed to the PCT from the hyperbranched polysilane to the fullerene.

This study is a numerical study on the coagulation as well as the sedimentation effect of nanofluids using the Brownian dynamics method. Three cases are simulated, focusing on the effects of the sizes, volume fraction, and ζ potentials of nano-particles on the formation of coagulation and sedimentation of nanofluids. The rms fluctuation of the particle number concentration, as well as the flatness factor of it, is employed to study the formation and variation of the coagulation process. The results indicate a superposition of coagulation and sedimentation effect of small nano-particles. Moreover, it is stable of nanofluids with the volume fraction of particles below the limit of "resolution" of the fluids. In addition, the effect of ζ potentials is against the formation of coagulation and positive to the stability of nanofluids.

Multiscale simulations using the quasicontinuum (QC) method with the embedded-atom method (EAM) potential are performed to investigate the process of nanocontact including sliding and subsequent withdrawal between Ni tip and Au substrate. The multiscale model reveals that deformation twinning in Au substrate is induced not only by the sheer stress but also by the adhesive stress. Combining with the generalized planar fault energy (GPF) curve of Au, the underlying formation mechanism of deformation twinning is studied in detail. During the withdrawal process, the dislocation degeneration and the vacancy evolution are observed.

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