Thermal insulating fibers can effectively regulate the human body temperature and decrease indoor energy consumption. However, designing super thermal insulating fibers integrating a sponge and aerogel structure based on biomass resources is still a challenge. Herein, a flow-assisted dynamic dual-cross-linking strategy is developed to realize the steady fabrication of regenerated all-cellulose graded sponge–aerogel fibers (CGFs) in a microfluidic chip. The chemically cross-linked cellulose solution is used as the core flow, which is passed through two sheath flow channels, containing either a diffusion solvent or a physical cross-linking solvent, resulting in CGFs with a porous sponge outer layer and a dense aerogel inner layer. By regulating and simulating the flow process in the microfluidic chip, CGFs with adjustable sponge thicknesses, excellent toughness (26.20 MJ m–3), and ultralow thermal conductivity (0.023 W m–1 K–1) are fabricated. This work provides a new method for fabricating graded biomass fibers and inspires attractive applications for thermal insulation in textiles.

Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustainable materials combining functional and structural performance. Cellulose nanofibril-graphene oxide (CNF-GO) nanocomposite films are prepared by a...

Transparent wood biocomposites based on PMMA combine high optical transmittance with excellent mechanical properties. One hypothesis is that despite poor miscibility the polymer is distributed at the nanoscale inside the cell wall. Small-angle neutron scattering (SANS) experiments are performed to test this hypothesis, using biocomposites based on deuterated PMMA and “contrast-matched” PMMA. The wood cell wall nanostructure soaked in heavy water is quantified in terms of the correlation distance d between the center of elementary cellulose fibrils. For wood/deuterated PMMA, this distance d is very similar as for wood/heavy water (correlation peaks at q ≈ 0.1 Å –1 ). The peak disappears when contrast-matched PMMA is used, indeed proving nanoscale polymer distribution in the cell wall. The specific processing method used for transparent wood explains the nanocomposite nature of the wood cell wall and can serve as a nanotechnology for cell wall impregnation of polymers in large wood biocomposite structures.