Multifunctional Superelastic Cellulose Nanofibrils Aerogel by Dual Ice‐Templating Assembly

Abstract

A superelastic aerogel with fast shape recovery performance from large compressive strain is highly desired for numerous applications such as thermal insulation in clothing, high-sensitive sensors, and oil contaminant removal. Fabrication of superelastic cellulose nanofibrils (CNF) aerogels is challenging as the CNF can assemble into non-elastic sheet-like cell walls. Here, a dual ice-templating assembly (DITA) strategy is proposed that can control the assembly of CNF into sub-micrometer fibers by extremely low temperature freezing (-196 °C), which can further assemble into an elastic aerogel with interconnected sub-micron fibers by freezer freezing (−20 °C) and freeze drying. The CNF aerogel from the DITA process demonstrates isotropic superelastic behavior that can recover from over 80% compressive strain along both longitudinal and cross-sectional directions, even in an extremely cold liquid nitrogen environment. The elastic CNF aerogel can be easily modified by chemical vapor deposition of organosilane, demonstrating superhydrophobicity (164° water contact angle), high liquid absorption (489 g g −1 of chloroform absorption capacity), self-cleaning, thermal insulating (0.023 W (mK) −1 ), and infrared shielding properties. This new DITA strategy provides a facile design of superelastic aerogels from bio-based nanomaterials, and the derived high performance multifunctional elastic aerogel is expected to be useful for a wide-range of applications.

Robust SiO2–Al2O3/Agarose Composite Aerogel Beads with Outstanding Thermal Insulation Based on Coal Gangue

“…As aerogels are generally used for thermal insulation because of their light weight and highly porous internal structures [ 39 ], the thermal insulating performance of the aerogel was further evaluated. The influence of SCAB-4 in inhibiting heat transfer was demonstrated by placing a pure putty block (PPB) and putty block containing SCABs (PBCS) with similar thicknesses (7 mm) on either a cold (carbon dioxide ice cube at −60 °C as shown in Figure 9 b) or hot plate with different temperatures, as shown in Figure 9 c. The heat transfer through the putty blocks was visualized using an infrared camera (FLIR) on top of a hot surface when the temperatures of the samples remained constant for approximately 15 min.…”

Fibrous Aerogels for Solar Vapor Generation

“…Unidirectional freezing produces uniaxial aligned ice crystals, with the pore structure orienting along a single direction, which benefits water transport and thermal insulation ( Jiang et al, 2018 ). This method has been used to construct fibrous building blocks such as cellulose, polymer nanofibers, and inorganic nanofibers ( Long et al, 2018 ; Qin et al, 2021 ; Liu et al, 2022 ). Ice templating is a versatile manufacturing technique, but the time and energy consuming properties of this method limits the large-scale production of materials.…”

Wires with Continuous Sabal Leaf‐Patterned Micropores Constructed by Freeze Printing for a Wearable Sensor Responsible to Multiple Deformations

“…[ 29–31 ] Moreover, ice templating methods have the capability to program the size, distribution and orientation of pores, which offers us a great opportunity to fabricate designed conductive porous structures for wearable sensors. [ 20,31,34,35 ]…”

“…[29][30][31] Moreover, ice templating methods have the capability to program the size, distribution and orientation of pores, which offers us a great opportunity to fabricate designed conductive porous structures for wearable sensors. [20,31,34,35] Herein, we report a technique termed freeze printing that enables the fabrication of round wire with long-rangeThe design of porous structure in wearable sensors is very important for the detection of mechanical signals. However, it remains challenging to construct a porous structure capable of detecting all kinds of mechanical signals.…”

“…[29][30][31] Moreover, ice templating methods have the capability to program the size, distribution and orientation of pores, which offers us a great opportunity to fabricate designed conductive porous structures for wearable sensors. [20,31,34,35] Herein, we report a technique termed freeze printing that enables the fabrication of round wire with long-range…”