A design and optimization of photo-thermal energy conversion components using textile fiber is very important in solar thermal energy conversion technology. In this study, an innovative bionic photo-thermal energy conversion model based on polar bears hair (Ursus maritimus) energy conversion mechanism has been explored and optimized. Besides, a processing technology and wave guiding principle using this new model were investigated to enhance the solar-thermal energy utilization property. Specifically, the fluorescent property, reflectivity and photo-thermal conversion property of the selected fabricating materials were measured and demonstrated in detail. The experimental results showed that this proposed new model worked well to design high-efficiency photo-thermal energy conversion devices. Also the bionic materials exhibited a high photo-thermal converting efficiency as well as outstanding heat insulation properties.

AbstractThe unique photo-thermal energy conversion property of polar bear hairs has long been regarded as an essential element to enable this creature to survive in extremely cold conditions. However, the relevant research was ineffectual to provide sufficient evidence of its solar energy harvesting property. In this paper, the properties of polar bear hairs were analyzed and compared systematically with those of domestic sheep wool through the measurements in the aspects of photo-thermal conversion efficiency, scanning electron microscope, fluorescence spectral and transmission of UV-visible spectra. Moreover, this study was much more focused on exploring ultraviolet utilization property of polar bear hair than previous research. The research results demonstrated that the photo-thermal property of polar bear hair was superior to those of wool fiber, especially in harvesting ultraviolet part. The potential benefits of this research lie in the development of bionic solar energy collective devices, especially in artificial solar energy collection fibers and textile products.

Ramie fiber-reinforced polylactic acid (PLA) composites were successfully prepared by hot compression molding. Different treatment techniques were used to modify the surface of ramie fiber. The influence of diammonium phosphate (DAP) on the interfacial adhesion between ramie fiber and PLA composites was investigated by the contact angle measurements, FTIR and SEM analyses. The contact angle measurement results showed that alkali treatment combined with DAP was very efficient in decreasing the hydrophilicity of fibers. After treatment, the hydrophilicity of untreated ramie fiber from 5.9 ± 1.3 decreased to 2.0 ± 0.8 mJ/m2. The wettability of alkali/silane/DAP-treated ramie fiber/PLA composite was higher (95.4° ± 1.3°) than that of pure ramie fiber/PLA composite (87.3° ± 1.9°). The FTIR results were consistent with the wetting measurements as the increment of hydrophilicity. Thermal analysis indicated that DAP-modified ramie fiber/PLA composites exhibited a lower thermal decomposition temperature, unique decomposition behavior and more residual char formation at decomposition temperature. The tensile, flexural and impact properties of DAP-modified ramie fiber composites were comparable to those of untreated ramie fiber composite. Moreover, proper alignment and uniform distribution of ramie fibers within the PLA matrix were found to be excellent. The morphological structures observed by SEM showed that well-modified ramie fibers enhanced the failure of the PLA composites in tensile, flexural and impact tests.

Thermo-sensitive polymer-grafted carbon nanotubes were prepared by surface-initiated atom transfer radical polymerization and carefully characterized. A reversible, temperature-induced phase transfer behavior of these organic–inorganic hybrids between water (with a decrease in temperature to 20 °C) and a hydrophobic ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim]NTf2) (with an increase in temperature to 90 °C), was observed. Mechanism analysis suggests that this reversible phase transfer between water and [Emim]NTf2 is due to the relative affinity of the two solvents for the poly(ethylene oxide) units grafted on the carbon nanotubes. Our results pave the way for further design of carbon nanotube-based, recyclable phase transfer vehicles as well as heterogeneous catalysts suited for a water–hydrophobic ionic liquid biphasic system.Keywords: atom transfer radical polymerization; carbon nanotube; ionic liquid; phase transfer; thermo-sensitive;