摘要
In this work,thermally insulating and electrically conductive aerogels were prepared from cellulose nanofibers(CNF)and carbon nanotubes(CNTs)by environmentally friendly freeze-drying process.The thermal conductivity of neat CNF aerogel is 24 mW/(m・K)with a density of 0.025 g/cm3.With the addition of CNTs into CNF aerogel,the electrical conductivity was significantly increased while the thermal conductivity was increased to 38 mW/(m・K).Due to these interesting properties,the Seebeck coefficient and the figure of merit(ZT)of the CNF/CNTs aerogels were measured and showed that CNF/CNTs aerogel thermoelectric properties can be improved.The compressibility and electrical resistance of the CNF/CNTs aerogel highlighted its pressure-responsive property.A set of volatile organic compounds(VOCs)were exposed to aerogels to monitor the resistance change.The CNF/CNTs aerogel showed high sensitivity and good response to both nonpolar and polar vapors due to the absorption by both CNF and CNTs networks.The prepared CNF/CNTs aerogel is therefore a good candidate for thermal insulation,thermoelectric material,VOCs sensing,and pressure-sensing applications.
