Liquid Polymer Nanocomposites PEGME-SnO2 and PEGME-TiO2.pdf

Liquid Polymer Nanocomposites PEGME-SnO2 and PEGME-TiO2 Prepared through Solvothermal Methods Huan-Ming Xiong, Wei-Zhi Shen, Zi-Dong Wang, Xiao Zhang, and Yong-Yao Xia* Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and InnoVatiVe Materials, Fudan UniVersity, Shanghai 200433, People’s Republic of China ReceiVed February 21, 2006. ReVised Manuscript ReceiVed May 23, 2006 A large number of polyether groups are modified on SnO2 and TiO2 nanocrystals through sol-gel methods and solvothermal treatments to form the stable liquid nanocomposites poly(ethylene glycol) methyl ether (PEGME)-SnO2 and PEGME-TiO2. These transparent viscous liquids can be dissolved by organic solvents, and the resulting colloids are also very stable; these nanocomposites themselves are able to dissolve lithium salts to form liquid electrolytes which have good ionic conductivities for practical applications. The conductive mechanism for such liquid electrolytes is regarded as ion transfer under the assistance of the PEGME group motion, which is totally different from that for the typical ionic liquids and the traditional liquid electrolytes based on organic solvents and metal salts. Introduction The integration of organic and inorganic materials, espe- cially polymers and nanoparticles, has led to revolution in materials science. 1,2 Such integration is able to make the entire polymer nanocomposite material inherit merits of both polymers and nanoparticles and even exhibit unexpected properties. But polymer nanocomposites are usually solids at ambient temperature, and thus their applications are inhibited when liquids, for example, ferrofluids and elec- trolytes, are required. Only recently, some liquid inorganic- organic nanocomposites have been investigated as a new type of electrolyte. 3-5 These nanocomposites are composed of transition-metal oxide nanoparticles or nanoclusters and organic ionic liquids (but not polymers) which coordinate with the metal atoms through