Hai Duong1

1, National University of Singapore, Singapore, , Singapore

A direct and scalable floating catalyst method to fabricate the self-supporting carbon nanotube (CNT) aerogels at higher deposition rates is developed successfully. The whole fabrication process takes only about 1-2 hours and can produce meter-long CNT aerogels continuously without using freeze drying and supercritical drying processes. The undeniable advantages of the established process also include its precise control of the amount of impurities and morphology of the CNT aerogel. With different collecting techniques and after the post treatments, we can produce the super strong km-long CNT fibers and also meter-scale aligned CNT thin films with their excellent multi-properties. The density of the aerogels ranges from 0.55 to 32 mg/cm3 with high porosity (>98%) and surface area of up to 170 m2/g. The CNT aerogels are not brittle, easy on handling and even the lightest ones can withstand a weight of ~150 times higher than their own (~15000 times higher than its density) without collapsing. The thermal and electrical conductivities are also quantified and better than those reported for the CNT aerogel coated with graphene, pure graphene- or graphene/CNT aerogels, and other CNT aerogels synthesized using the freeze-drying and critical point-drying methods.

Also cellulose aerogels from environmental waste for several applications such as oil spill cleaning and thermal insulation of buildings are developed successfully. A more facile, cost effective, much less time-consuming fabrication method is innovated. The continuous and large-scale process takes only three days and uses much less non-toxic chemicals such as recycled cellulose fibers from paper- or fabric- waste, water and Kymene as a cross-linker. The MTMS-coated aerogels can absorb oil excluding water 4 times larger than that of the best commercial sorbents. The cellulose aerogels can be squeezed to recover over 99% of absorbed crude oil. Thermal conductivities of 1.0 - 4.0 wt.% cellulose aerogels are 0.034 - 0.037 W/m.K. The water-repellent aerogel structures are stable over 6 months in tropical climate. The compressed cellulose aerogel in the tablet form can be effective to be used to haemorrhage control. This technology gives a promising solution for the global environmental pollution and energy problems.