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Aerogels have many attractive properties but are usually costly and too friable, which always limit their practical applications. Besides, almost all of the reinforced aerogels sacrifice the transparency or superinsulating properties. Here we report unprecedented superflexible polyvinylpolymethylsiloxane ((CH2CH)n(CH3)SiO2/2) aerogels that are facilely prepared from a single precursor vinylmethyldimethoxysilane or vinylmethyldiethoxysilane without organic crosslinkers. It is based on a consecution of radical polymerization and hydrolytic polycondensation followed by ultralow-cost, highly scalable ambient pressure drying directly from alcohol as a drying medium without any modification and additional solvent exchange. The resulting aerogels and xerogels show a unique, homogeneous, tunable, highly porous, doubly crosslinked nanostructure with the elastic polymethylsiloxane network crosslinked with flexible hydrocarbon chains. An outstanding combination of ultralow cost, high scalability, uniform pore size, high surface area, high transparency, high hydrophobicity, excellent machinability, superflexibility in compression, superflexibility in bending and superinsulating properties has been achieved in a single aerogel and xerogel for the first time. This study represents a significant progress of porous materials and makes the practical applications of transparent flexible aerogel-based superinsulators realistic., The title of a Submitted Work is 'Ultralow-cost, Highly Scalable, Transparent, Superflexible Doubly Crosslinked Polyvinylpolymethylsiloxane Aerogel Superinsulators'

A facile yet versatile approach to transparent, highly flexible, machinable, superinsulating organic-inorganic hybrid aerogels and xerogels is presented. This method involves radical polymerization of a single alkenylalkoxysilane to obtain polyalkenylalkoxysilane, and subsequent hydrolytic polycondensation to afford a homogeneous, doubly cross-linked nanostructure consisting of polysiloxanes and hydrocarbon polymer units. Here we demonstrate that novel aerogels based on polyvinylpolysilsesquioxane (PVPSQ), polyallylpolysilsesquioxane (PAPSQ), polyvinylpolymethylsiloxane (PVPMS), and polyallylpolymethylsiloxane (PAPMS) are facilely prepared via this approach from vinyltrimethoxysilane (VTMS, or vinyltriethoxysilane VTES), allyltrimethoxysilane (ATMS, or allyltriethoxysilane ATES), vinylmethyldimethoxysilane (VMDMS), and allylmethyldimethoxysilane (AMDMS), respectively. These aerogels combine low density, uniform nanopores, high transparency, super-compressibility, high bendability, excellent machinability, and thermal superinsulation (λ=14.5-16.4 mW m−1 K−1). More importantly, transparent, superflexible, superinsulating aerogel-like xerogels are obtained with PVPMS and PAPMS via highly scalable ambient pressure drying without any solvent exchange and modifications for the first time. This work will open a new way to transparent, highly flexible porous materials promising in the practical applications of thermal superinsulators, adsorbents, sensors, etc., The title of the Submitted Work is 'A Versatile Double-Cross-Linking Approach to Transparent, Machinable, Super-Compressible, Highly Bendable Aerogel and Xerogel Thermal Superinsulators'

以低成本工业级硅溶胶为硅源, 水为溶剂, 在常压条件下干燥后制备出纳米多孔SiO 2 块体材料。在制备过程中, 采用表面活性剂十六烷基三甲基溴化铵(CTAB)来降低水的表面张力, 减少样品在干燥过程中开裂和收缩, 避免了繁琐的溶剂替换过程。所制备的SiO 2 块体密度为150~260 mg/cm 3 , 比表面积为91~140 m 2 /g, 平均孔径为15~27 nm, 其室温热导率可达0.048 W/(m·K)。该方法大大缩减了制备SiO 2 纳米多孔材料的成本, 并降低了操作工艺难度和危险, 将在很大程度上推动硅纳米孔材料的工业化生产与应用。