Robust Nanofibrillated Cellulose Hydro/Aerogels from Benign Solution/Solvent Exchange Treatment

Abstract

To fabricate robust nanofibrillated cellulose (NFC) hydro/aerogels, benign solution/solvent exchange treatment was developed by adding five different water miscible solutions/solvents into a NFC aqueous suspension. The NFC self-aggregated and formed self-standing gels during the solution/solvent exchange treatment. After a further exchange of solution/solvent inside the gels with water by a thorough water washing followed by freeze-drying, NFC hydrogels and aerogels were obtained. The NaOH-hydrogel demonstrated a decent rheology with a storage modulus of 36.4 kPa and a satisfactory mechanical property with a compressive modulus of 37.6 kPa. On the contrary, the acetone-hydrogel was weak due to disaggregation. The NFC aerogels were lightweight and had a characteristic porous structure. The packing density and structure varied among aerogels with different solution/solvent treatments. The NaOH-aerogel had a 2D sheet-like structure with densely packed micrometer-sized pores uniformly distributed within the aerogel network, which demonstrated a high compressive strength. However, the structures of other aerogels were loose, leading to a low compressive strength. These NFC aerogels demonstrated high thermal stability and superior performance for efficient thermal insulation. We believe our work can stimulate interest in the development of NFC hydro/aerogels with multiple structures, properties, and functions for a variety of applications.

Highly Compressible, Thermally Stable, Light-Weight, and Robust Aramid Nanofibers/Ti3AlC2 MXene Composite Aerogel for Sensitive Pressure Sensor

“…Thermal conductivity of the 0, 30, and 50 wt % MXene/ANFs aerogel sensors. (b) Thermal conductivity comparison between the MXene/ANFs aerogel and other typical aerogels (PMSQ aerogel, PVPMS aerogel, NFA aerogel, PI aerogel, PVA/CNF/GONS aerogel, polyamide aerogel, KNF aerogel mat, NFC aerogel, FPU aerogel, silica aerogel, SiO 2 /PVDF aerogel, carbon aerogel, cellulose/SiO 2 aerogel). (c 1 –c 3 ) Infrared thermal imager photos of the 30 wt % MXene/ANFs aerogel in axial and radial directions when placed on a stable heating source at 200 °C.…”

“…As a promising multifunctional sensor, the MXene/ANFs aerogel sensor possesses a prominent thermal insulating property, which was assessed by placing it on a stable heating source with a high temperature of 200 °C, as shown in Figure 6c. 48 PVPMS aerogel, 49 NFA aerogel, 50 PI aerogel, 51 PVA/CNF/ GONS aerogel, 52 polyamide aerogel, 53 KNF aerogel mat, 54 NFC aerogel, 55 FPU aerogel, 56 silica aerogel, 57 SiO 2 /PVDF aerogel, 58 carbon aerogel, 59 cellulose/SiO 2 aerogel 60 ). 6c 1 −c 3 .…”

Nanostructure of Aerogels and Their Applications in Thermal Energy Insulation

“…Finally, the concentration of CNF at 1 wt % is an optimum point for thermal insulation performance. NaOH, NaCl, HCl, acetic acid (HAc), and acetone are considered as a solution/solvent to exchange with distilled water by Fan et al 138 The 1 wt % CNF (from poplar wood) suspension is prepared, and then 15 wt % NaOH, 15 wt % NaCl, 1 M HCl solution, HAc, and acetone are separately poured into suspension to form gels. After washing with distilled water, five different hydrogels are fabricated and placed in a refrigerator.…”

Influence of Xyloglucan Molar Mass on Rheological Properties of Cellulose Nanocrystal/Xyloglucan Hydrogels

“…They already found uses on cosmetics and also have variety of applications such as in chromatography, food and also in domestic uses [24]. Cellulose based hydrogels have been already reported thanks to their high strength, large specific surface, and tunable surface chemistry, allowing controlled interactions with various building blocks to achieve materials with tunable and efficient properties [3,25]. CNC based hydrogels can be implemented through chemical or physical pathway among which polymer addition has been reported as efficient strategy [26,27].…”