Commercial Silk-Based Electronic Yarns Fabricated Using Microwave Irradiation

Charge transport in pyroprotein-based electronic yarns

Pyroprotein-based carbon materials produced by heat-treating silk proteins have many potential applications in electronic devices, such as electronic textiles. To further develop potential electronic devices using these pyroproteins, the charge transport mechanism has to be verified. However, the electrical characteristics of the pyroproteins have not been reported yet. In this study, the temperature-dependent charge transport behavior of pyroprotein-based electronic yarns prepared from commercial silks (e-CS yarns) is investigated with respect to various heat treatment temperatures (HTT, 800, 1000, 1200, and 1400 °C). The linear current-voltage properties are shown at a low bias of 100 nA from 9 K to 300 K. The temperature-dependent resistivity of the e-CS yarns can be clearly described by the crossover of 3-dimensional Mott variable range hopping and fluctuation-induced tunneling conduction at the crossover temperature (Tc). These Tc factors are significantly different, due to the structural modulation of the e-CS yarns depending on the HTT, and are characterized by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. This study is expected to provide a better understanding of the electrical properties of pyroproteins.

Microwave irradiation assisted sodium hexametaphosphate modification on the alkali-activated blast furnace slag for enhancing immobilization of strontium

An inadvertent leakage of ⁹⁰Sr into the environment can induce an easy accumulation in biosphere and cause a continuous radiation to the surrounding ecosystem. In this study, sodium hexametaphosphate (Na₆O₁₈P₆) was employed to modify the blast furnace slags (BFS) to enhance the chemical stabilization of Sr²⁺ ions in the BFS-based cementitious materials. Microwave irradiation (MW) was used to further increase the binder activity of BFS samples and strengthened the mechanical strengths and durability of BFS-based blocks. A combination of experimental factors including the mass ratio of Na₆O₁₈P₆ to BFS-Sr_0.1 of 15%, the ratio of solid to liquid of 1:4 mg/L, the output power of 650 W, and the activation time of 3 min was most conductive to achieving an optimal microwave-irradiation process. Four extraction solutions were sorted by their leaching abilities following as MgSO₄ solution > H₂SO₄ solution > CH₃OOH solution > deionized (DI) water based on their leaching results. Compared with microwave irradiation, an addition of Na₆O₁₈P₆ to BFS samples obtained a better compressive strength for BFS-based blocks. However, a microwave-irradiation treatment was more effective in improving the resistances of blocks to gamma irradiation and thermal-thaw changes. Exposing to gamma irradiation over 6 months and enduring to thermal-thaw tests over 15 cycles, the microwave-treated blocks only lost 3.29% and 2.23% of leaching removal efficiencies in deionized water, respectively. Microwave irradiation increased the mechanical strengths of BFS-based blocks and inhibited leaching of Sr²⁺ ions from matrices mainly by strengthening hydration reactions and Sr²⁺ encapsulation.