“Stiff–Soft” Binary Synergistic Aerogels with Superflexibility and High Thermal Insulation Performance

Abstract

Designing aerogel materials featuring both high thermal insulation property and excellent mechanical robustness is of great interest for applications in superior integrated energy management systems. To meet the above requirements, composite aerogels based on hierarchical “stiff–soft” binary networks are reported, in which secondary mesoporous polymethylsilsesquioxane domains intertwined by bacterial cellulose nanofibrillar networks are connected in tandem. The resulting composite aerogels are characterized by highly porous (93.6%) and nanosized structure with a surface area of 660 m2 g−1, leading to the excellent thermal insulation performance with a low thermal conductivity of 15.3 mW m−1 K−1. The integrated “stiff–soft” binary nature also endows the composite aerogels with high flexibility that can conform to various substrates as well as large tensile strength that can withstand more than 2.70 × 104 times its own weight. These composite aerogels show multifunctionality in terms of efficient wearable protection, controllable thermal management, and ultrafast oil/water separation. These favorable multifeatures present composite aerogels ideal for aerospace, industrial, and commercial applications.

Thermal Insulation Characteristics of Polybenzoxazine Aerogels

“…In general, the thermal conductivity of aerogel in the air is contributed by solid heat, gas heat, and radiation transfers . The contributions of radiation transfer can be neglected at ambient temperatures . The heat transfers by the solid and gas phase constitute the final thermal conductivity.…”

“…[32] The contributions of radiation transfer can be neglected at ambient temperatures. [33,34] The heat transfers by the solid and gas phase constitute the final thermal conductivity. The gas heat transfer includes gas molecule and convection heat transfers.…”

Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment

“…One common and representative example summarized here, in which the programmed functionalities were enabled by a structural modification in molecular, [155,191] nano/microdimensional, [81,139,184,203,212,222] and device group levels, [130] already plays a key part in managing multiple interface-related conditions and suitable methodologies. Parallel efforts in the development of intrinsically stretchable, transparent, or selfhealable electronics are focusing on the successful integration of multimodal materials exhibiting liquid-like, [151] ionic conducting, [224] and biomimetic behaviors [192] as electrodes, substrates, dielectrics, and transistors. These devices are promising for next-generation biomedical systems and persistent humanmachine interfaces.…”

“…[102] As for an aerogel, Zhang et al reported a wearable flexible carbon black aerogel composite that affords its thermal insulation property and thus thermal protection better than cotton fabrics. [224] This composite showed hydrophobicity and ultrafast oil/water separation capability owing to its abundant methyl groups on the surface and high porosity (93.6%). Furthermore, a recent study showed that the hydrophobic polymer coating method stabilized LM NPs for more than 60 days.…”

Robust Silica-Cellulose Composite Aerogels with a Nanoscale Interpenetrating Network Structure Prepared Using a Streamlined Process

“…The above two strategies will also be used in combination to better improve the mechanical properties of silica aerogels [30]. More recently, conformal coating of the silica gel skeleton with a polymer [31] and the construction of a nanoscale interpenetrating network (IPN) [32][33][34] have been proposed. The conformal polymer coating method strengthens the gel skeleton and preserves the mesopores of silica aerogels.…”