Ultra-Porous Nanocellulose Foams: A Facile and Scalable Fabrication Approach

摘要: Cellulose nanofibril foams are cellulose-based porous materials with outstanding mechanical properties, resulting from the high strength-to-weight ratio of nanofibrils. Here we report development an optimized fabrication process for highly cellulose foams, based on a well-controlled freeze-thawing-drying (FTD) at ambient pressure. This enables ultra-high porosity, up to 99.4%, density 10 mg/cm3, and liquid (such as oil) absorption capacity 100 L/kg. The proposed approach is ice-templating nanocellulose suspension in water, followed by thawing ethanol drying environmental pressures. As such, route overcomes one major bottle-necks classical freeze-drying approach, eliminating energy-demanding vacuum step required avoid wet foam collapse upon drying. result, simple, environmentally friendly, easily scalable. Details functionalization thoroughly discussed, highlighting main parameters affecting process, e.g., concentration additives used control ice nucleation. also characterized tests oil measurements, which assess capability well porosity. Compound water-in-oil drop impact experiments demonstrate potential immiscible separation using foams.