生物基气凝胶是一种功能化的纳米多孔材料,高表面积,超低密度,高孔隙率,和低热导率,使其适用于各种应用,如节能建筑,电子信息,分离,吸附,催化作用,生物医学,和其他人。然而,目前的生物基壳聚糖气凝胶在实现多功能改进以解决其固有缺点方面仍面临巨大挑战。在这里,我们提出了一种基于超分子相互作用的新方法,用于构建壳聚糖/细菌纤维素气凝胶,同时具有优异的防潮性/疲劳性,抗热冲击,和阻燃性。具体来说,气凝胶表现出显著的特性,即高强度(自立自重超过10676倍),低热导率(在常压和室温下最低至22mWm-1K-1),和优异的抗疲劳性(在1%应变下几乎可以忽略不计的永久变形,即使经历高达10,000次的压缩循环)。另一方面,气凝胶具有超疏水性(在70°C和85%相对湿度下160小时的吸湿率<0.88%),出色的热冲击性能(可承受多达200次冷热冲击,温度在-30°C至60°C之间快速变化),和显着的阻燃性(迅速自我熄灭在0.6秒)。此外,疏水处理后,压缩应力在3%应变下增加到0.223MPa,表示机械坚固性增强了27%。Further,在不同的菌株条件下也建立了负责微观结构演化的机制。这项工作可以为开发用于节能建筑的多功能生物基气凝胶提供丰富的可能性。
Bio-based aerogel is a functionalized nanoporous material with environmentally friendly, high surface area, ultra-low density, high porosity, and low thermal conductivity, making it suitable for various applications such as energy-saving buildings, electronic information, separation, adsorption, catalysis, biomedicine, and others. However, the current bio-based chitosan aerogel still faces great challenges in reaching multifunctional improvement to address its intrinsic shortcomings. Herein, we propose a new approach depending upon supramolecular interactions for constructing chitosan/bacterial cellulose aerogels that simultaneously possess superior moisture resistance/fatigue, anti-thermal-shock, and flame retardancy. Specifically, the aerogels demonstrate remarkable characteristics, namely high strength (self-standing itself weight beyond 10,676 times), low thermal conductivity (lowest to 22 mW m-1 K-1 under normal pressure and room temperature), and excellent fatigue resistance (almost negligible permanent deformation at 1 % strain even undergoing compressive cycles up to 10,000 times). On the other hand, the aerogels display exceptional moisture resistance with superhydrophobicity (moisture absorption rate <0.88 % for 160 h at 70 °C and 85 % relative humidity), excellent thermal shock property (withstand cold-hot shock up to 200 cycles with rapid temperature changes between -30 °C and 60 °C), and remarkable fire retardancy (swiftly self-extinguishing in 0.6 s). Additionally, the compressive stress increases to 0.223 MPa at 3 % strain after hydrophobic treatment, representing a 27 % enhancement in mechanical robustness. Further, the mechanism responsible for microstructural evolution has been also established in different strain conditions. This work may provide rich possibilities for developing multifunctional bio-based aerogel for energy-saving buildings.