Efficient enhancement of the toughness of epoxy resins has been a bottleneck for expanding their suitability for advanced applications. Here, polysulfone (PSF) was adopted to toughen and modify the epoxy. The influences of PSF on the mechanical and thermal properties of the epoxy resin were systematically studied by optical microscopy, Fourier transform infrared spectrometer (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TG), dynamic mechanical thermal analyzer (DMA), mechanical tests and scanning electron microscope (SEM). The dissolution experimental results showed that PSF presents a good compatibility with the epoxy resin and could be well dissolved under controlled conditions. The introduction of PSF was found to promote the curing reaction of the epoxy resin without participating in the curing reaction and changing the curing mechanism as revealed by the FT-IR and DSC studies. The mechanical properties of PSF/epoxy resin blends showed that the fracture toughness and impact strength were significantly improved, which could be attributed to the bicontinuous phase structure of PSF/epoxy blends. Representative phase structures resulted from the reaction induced phase separation process were clearly observed in the PSF/epoxy blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PSF content. Our work further confirmed that the thermal stability of the PSF/epoxy blends was slightly increased compared to that of the pure epoxy resin, mainly due to the good heat resistance of the PSF component.

Polylactic acid (PLA) is one of the most promising bio-based materials, but its inherent hydrophobicity limits its application. Although nanocellulose (NCC) is a desirable reinforcement for PLA, the poor interface compatibility between the two has been a challenge. In this work, hydroxyapatite (HAP) modified NCC was prepared, and the obtained NCC/HAP reinforcement was used to prepare PLA/NCC-HAP composites. Different ratios of NCC to HAP were studied to explore their effects on the mechanical and thermodynamic properties of the composites. When the ratio of NCC to HAP was 30/70, the tensile strength and tensile modulus of the composite film reached 45.6 MPa and 2.34 GPa, respectively. Thermogravimetric analysis results indicate that thermal stability of the composites was significantly improved compared with pure PLA, reaching 346.6 °C. The above revelations show that NCC/HAP significantly improved the interface compatibility with PLA matrix.

Perovskite-based solar cells with high power conversion efficiencies (PCEs) are currently being demonstrated in solid-state device designs. Their elevated performances can possibly be attained with different non-standard geometries, for example, the fiber-shaped perovskite solar cells, in the light of careful design and engineering. Fiber-shaped solar cells are promising in smart textiles energy harvesting towards next-generation electronic applications and devices. They can be made with facile process and at low cost. Recently, fiber-shaped perovskite solar devices have been reported, particularly with the focus on the proof-of-concept in such non-traditional architectures. In this line, there are so many technical aspects which need to be addressed, if these photovoltaic (PV) cells are to be industrialized and produced massively. Herein, a well-organized and comprehensive discussion about the reported devices in this arena is presented. The challenges that need to be addressed, the possible solutions and the probable applications of these PV cells are also discussed. More still, the perovskite fiber-shaped PV cells with other fiber PV devices reported in literature in terms of their scope, characteristic designs, performances, and other technical considerations have been summarised.

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