胶原静电纺丝研究进展

胶原是细胞外基质的主要结构蛋白,广泛存在于各类动物机体中。天然胶原存在纤维形态不一、机械性能差等不足,限制了其工业规模化应用。因此,如何有效地制备出性能优良的胶原材料成为热点问题。静电纺丝技术是一种新兴的纳米材料制造技术,利用该技术可获得具有不同结构和性能的胶原基纳米纤维材料,制成的纳米纤维材料展现出密度低、弹性高等优异特性,有望广泛应用于组织工程、医学、载体等领域。本文将从胶原的单独静电纺丝及其影响因素、胶原共混静电纺丝和影响因素以及应用等方面介绍胶原静电纺丝技术的研究进展,并针对存在的问题和发展方向进行了讨论和展望,为胶原的应用提供一定的理论指导和技术支撑。     

Elastocaloric effect and mechanical behavior for NiTi shape memory alloys

The NiTi shape memory alloy exhibits excellent superelastic property and elastocaloric effect. The large temperature change(DT) value of 30 K upon loading and-19 K upon unloading are obtained at room temperature, which are higher than those of the other NiTi-based materials and among the highest values reported in the elastocaloric materials. The asymmetry of the measured DT values between the loading and unloading process is ascribed to the friction dissipation.The large temperature change originates from the large entropy change during the stress-induced martensite transformation(MT) and the reverse MT. A large coefficient-of-performance of the material is obtained to be 11.7 at ε= 1%, which decreases with increasing the applied strain. These results are very attractive in the present solid-state cooling, which potentially could replace the vapor compression refrigeration technologies.