Small-angle X-ray scattering (SAXS) is an effective method to obtain microstructural information of materials. However, due to the influence of crystal surface effects, SAXS has a deviation in the characterization of the crystal microstructure. In order to solve the influence of crystal surface effect on the internal defect signal, the microstructure of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystal was characterized by soaking the sample in the matching solution. We found that the absolute scattering intensity, specific surface and volume fraction of the sample in the matching solution are significantly lower than the initial sample, which solves the influence of the crystal surface effect on the test results. Comparing the scattering results of the samples in different electron density matching solutions, it was found that the best result was obtained when using GPL-107 perfluoropolyether (PFPE) matching solution and the same law was obtained by controlling the experiment with 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) crystal. The fitting density was calculated according to the theoretical density and void volume fraction of the sample, and the calculated results are close to the test results of Particle Density Distribution Analyzer (PDDA). Based on this paper, we provide a method to obtain the correct information of crystal microstructure.

A bio-inspired conductive binary-network of vein–silver nanowires (AgNWs) was embedded in poly(dimethylsiloxane) (PDMS) to prepare a semi-transparent stretchable conductor (vein–AgNWs–PDMS) by a simple dipping process. The special conductive structure was constructed by using veins with a porous structure as an ideal skeleton to load AgNW networks, which allowed the vein–AgNWs–PDMS composite to show a low sheet resistance of 1 Ω sq⁻¹ with 74% transmittance. The figure of merit of vein–AgNWs–PDMS is as high as 2502 and can be adjusted easily by controlling the times of the dipping cycle. Furthermore, the vein–AgNWs–PDMS conductor can retain high conductivity after 150% mechanical elongation and exhibit excellent electromechanical stability in repeated stretch/release tests with 60% strain (500 cycles). As an example of an application, patterned light-emitting diode (LED) arrays using the vein–AgNWs–PDMS conductors have been fabricated, and worked well under deformation. Moreover, the photo-thermal properties of the vein–AgNWs–PDMS composite have been demonstrated by a position heating experiment using near-infrared (NIR) laser irradiation and the generated heat can be effectively dissipated through the vein network to avoid local overheating. Due to the high-performance and facile fabrication process, the vein–AgNWs–PDMS conductors will have multifunctional applications in stretchable electronic devices.

In order to obtain epoxy compounds with excellent mechanical properties without compromising other desired properties, pristine- or carboxyl-functionalized multi-walled carbon nanotube (p-MWCNT or f-MWCNT) along with polysulfide were incorporated into an amine-cured epoxy resin. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses proved the existence of carboxyl groups on the surface of f-MWCNT. Adding 0.1 wt% f-MWCNT significantly improved the tensile strength and impact strength of the epoxy nanocomposites by 104% and 47%, respectively. However, adding p-MWCNT had little effect on the mechanical properties of the nanocomposites. The glass transition temperature of the f-MWCNT/epoxy nanocomposites were also much higher than neat epoxy matrix and p-MWCNT/epoxy nanocomposites. The fracture surface morphology and dynamic mechanical analysis results indicated that the interfacial interactions between f-MWCNT and the epoxy matrix were much stronger than that of p-MWCNT, which ensured the much-improved mechanical properties.