通过给桑蚕喂食稀土离子改性的饲料制备高强高韧的蚕丝纤维

Highly strong and tough silk by feeding silkworms with rare earth ion-modified diets

蚕丝纤维具有优异的生物相容性和良好的力学性能,但以简单且大规模的方式生产强韧的蚕丝纤维仍是一项重大挑战.本文报道了一种通过给桑蚕喂食稀土离子改性桑叶饲料以制备强韧蚕丝纤维的方法.所得蚕丝纤维具有显著提高的拉伸强度和韧性,其平均值分别为0.85±0.07 GPa和156±13 MJ m^(-3),且最大值达到0.97±0.04 GPa和188±19 MJ m^(-3),这些性能接近蜘蛛牵引丝(自然界最强的丝纤维之一)的拉伸强度和韧性.研究结果表明,稀土离子(La^(3+)或En^(3+))成功掺入蚕丝纤维并与其形成相互作用.稀土离子减小了蚕丝纤维的直径,降低了其内部结晶组分的含量并提升了取向度.这些相互作用与结构演变同时提升了蚕丝纤维的强度和韧性.该研究提出了一种简单、可扩展且有效的生产超强韧丝纤维的策略,制备的蚕丝纤维有望应用于个人防护和航空航天等需要轻质结构材料的领域.

Nature-derived silk fibers possess excellent biocompatibility,sustainability,and mechanical properties,yet producing strong and tough silk fibers in a facile and large-scale manner remains a significant challenge.Herein,we report a simple method for preparing strong and tough silk fibers by feeding silkworms rare earth ion-modified diets.The resulting silk fibers exhibit significantly increased tensile strength and toughness,with average values of 0.85±0.07 GPa and 156±13 MJ m^(-3),respectively,and maximum values of 0.97±0.04 GPa and 188±19 MJ m^(-3),approaching those of spider dragline silk.Our findings suggest that the incorporation of rare earth ions(La^(3+) or Eu^(3+))into the silk fibers contributes to this enhancement.Structure analysis reveals a reduction in content and an improvement in orientation of b-sheet nanocrystals in silk fibers.X-ray photoelectron spectroscopy analysis confirms the chemical interaction between rare earth ions with b-sheet nanocrystals.The structural evolution and chemical interactions lead to the simultaneous enhancement in both strength and toughness.This work presents a simple,scalable,and effective strategy for producing ultra-strong and tough silk fibers with potential applications in areas requiring super structural materials,such as personal protection and aerospace.