State Key Laboratory of New Textile Materials and Advanced Processing Technologies, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, China.
Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States.
ACS Nano. 2021 May 25;15(5):8171-8183. doi: 10.1021/acsnano.1c00346. Epub 2021 Apr 13.
Nanofibrous aerogels have been extensively developed as multifunctional substrates in a wide range of fields. Natural silk nanofibrils (SNFs) are an appealing biopolymer due to their natural abundance, mechanical toughness, biodegradability, and excellent biocompatibility. However, fabricating 3D SNF materials with mechanical flexibility remains a challenge. Herein, SNF-based aerogels with controlled structures and well mechanical resilience were prepared. SNFs were extracted from silkworm silks by mechanical disintegration based on an all-aqueous system. The nanofibrils network and hierarchical cellular structure of the aerogels were tuned by the assembly of SNFs and foreign poly(vinyl alcohol) (PVA). The SNF aerogels exhibited an ultralow density (as low as 2.0 mg·cm) and well mechanical properties with a structure allowing for large deformations. These SNF aerogels demonstrated a reversible compression and stress retention after 100 cycles of compression. Furthermore, the resulting aerogels were used for air filtration and showed efficient filtration performance with a high dust-holding capacity and low resistance. Moreover, an extremely low thermal conductivity of 0.028 W·(m·K) was achieved by the aerogel, showing its potential for use in heat-retention applications. This study provides a useful strategy for exploring the use of natural silks in 3D aerogels and offers options for developing filtration materials and ultralight heat-retention materials.
纳米纤维气凝胶作为多功能基质已在广泛的领域中得到了深入的发展。天然丝纳米纤维（SNFs）由于其丰富的天然资源、机械韧性、生物降解性和优异的生物相容性，是一种很有吸引力的生物聚合物。然而，制造具有机械柔韧性的 3D SNF 材料仍然是一个挑战。在此，制备了具有可控结构和良好机械弹性的基于 SNF 的气凝胶。通过基于全水体系的机械分解从蚕茧丝中提取 SNFs。SNFs 的组装和外来聚（聚乙烯醇）（PVA）可以调节气凝胶的纳米纤维网络和分级多孔结构。SNF 气凝胶表现出超低密度（低至 2.0mg·cm）和良好的机械性能，具有允许大变形的结构。这些 SNF 气凝胶在 100 次压缩循环后表现出可恢复的压缩和应力保持。此外，所得气凝胶用于空气过滤，具有高粉尘保持能力和低阻力的高效过滤性能。此外，气凝胶的热导率低至 0.028W·(m·K)，表明其在保温应用方面有很大的应用潜力。这项研究为探索天然丝在 3D 气凝胶中的应用提供了一种有用的策略，并为开发过滤材料和超轻保温材料提供了选择。
