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Spherical bridged polysilsesquioxane (BPS) nanoparticles were prepared by the hydrolysis and condensation reaction of urethane-based BPS monomer made from 1, 4-butanediol and 3-(triethoxysily)propyl isocyanate. Polydopamine (PDA) was coated on the surfaces of BPS by the self-polymerization of dopamine under pure oxygen at room temperature. To create aggregates of Pd nanoparticles on PDA-coated BPS, polyhedral oligomeric silsesquioxane (POSS-NH3+) as a cross-linker was incorporated on the surfaces of PDA-coated BPS. Aggregates of Pd nanoparticles were densely produced on the surfaces of PDA-coated BPS by the mixing of POSS/PDA-coated BPS and palladium (Π) acetate in a methanol solution. [ABSTRACT FROM AUTHOR]

PAA-grafted MWNTs containing POSS (POSS/PAA-grafted MWNTs) were synthesized by the simple mixing of octa(3-aminopropyl)octasils-esquioxane (POSS-NH3+) and PAA-grafted MWNTs via ionic interactions. The spherical aggregates of Pd nanoparticles on the surface of POSS/PAA-grafted MWNTs (Pd-POSS/MWNTs) were produced with an average size of 10–20 nm due to the effect of POSS-NH3+used as a cubic linker physically attached to PAA-grafted MWNTs. The size of Pd-POSS/MWNTs was smaller than that of spherical aggregates of Pd nanoparticles prepared by only POSS-NH3+. The residual content of Pd-POSS/MWNTs is larger than that of POSS/PAA-grafted MWNTs because of the aggregates of Pd nanoparticles. [ABSTRACT FROM PUBLISHER]

A simple method was proposed for preparing aggregates of Pd nanoparticles on graphene oxide (GO) by mixing of palladium acetate and GO modified with polyhedral oligomeric silsesquioxane (POSS) (POSS-modified GO) in methanol. Spherical aggregates of Pd nanoparticles with a diameter 10-30 nm were densely produced on the surface of POSS-modified GO. POSS-modified GO was synthesized by the ionic interactions between negatively charged GO and positively charged POSS-NH . POSS-NH with silica-like core and eight organic functional groups on the surface of GO plays a role in making the spherical aggregates of Pd nanoparticles (Pd-POSS/GO). The residual content and thermal stability of Pd-POSS/GO were higher than that of GO and POSS-modified GO in thermogravimetric (TGA) analysis. The size of aggregates of Pd nanoparticles on the surface of POSS-modified GO is smaller than that of aggregates of Pd nanoparticles produced without GO template. POSS-modified GO and Pd-POSS/GO were fully characterized by Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, and TGA. [ABSTRACT FROM AUTHOR]

Spherical bridged polysilsesquioxane nanoparticles with thiol groups (BPS-SH) were prepared by the reduction of BPS with disulfide groups after the base-catalyzed hydrolysis and condensation reaction of bis(triethoxysilylpropyl)disulfide. The average size of BPS was around 100∼300 nm. Hydroxyethyl methacrylate (HEMA)-initiated polycaprolactone (PCL) was synthesized by ring-opening polymerization of caprolactone under the co-initiation of HEMA and Sn(Oct)2. New nanocomposites of BPS-SH and HEMA-PCL were fabricated by the photo-induced chemical reaction under a photoradical generator and ultraviolet light. BPS was fully and continuously covered with PCL, which resulted in the rough surface of BPS nanoparticles as well as the connected BPS nanoparticles together. [ABSTRACT FROM AUTHOR]

The rapid innovation of flexible smart electronics has increased the demand for flexible thermally conductive films with the high performance of electromagnetic interference shielding (EMI). This study focuses on graphene nanoplatelets/polyurethane (GnP/PU) films that were fabricated utilizing the solution casting approach. The stretching-induced alignment method was then used to align the GnP sheets horizontally in the PU matrix by uniaxially stretching to a particular degree. The resultant stretched GnP/PU films with 10 wt% GnP loading at a stretching degree of 130% show an excellent in-plane thermal conductivity (λ ∥) and EMI shielding effectiveness values of 10.68 W m−1 K−1 and 41 dB in the frequency range of 8–12 GHz which are 679% and 60%, respectively, higher than that of corresponding unstretched ones. The outstanding λ ∥ and EMI shielding effectiveness can be ascribed to the horizontal alignment of GnP sheets in the PU matrix. That, in turn, may decrease the interfacial thermal resistance, and facilitate the establishment of effective phonon and electron transfer in the stretched GnP/PU films. The obtained films demonstrated superior heat dissipation and mechanical properties compared to neat PU film. Therefore, the prepared GnP/PU films have great potential as heat spreaders and EMI shielding material in flexible smart electronics. [Display omitted] [ABSTRACT FROM AUTHOR]