Hydrophobic Organic Aerogels Based on Trimethoxy Benzene

Abstract

Aerogels are open porous nanostructured solids obtained by a sol-gel process followed by drying of the wet gel. They can be of inorganic or organic nature, rigid or flexible, translucent or opaque and are characterized by their remarkably low densities, low heat conductivities, high surface areas and low sound transmittance.[1] The most prominent example of an organic aerogel is the resorcinol-formaldehyde (RF) aerogel.[2] The phenolic nature of RF renders the material hydrophilic, a factor that partly limits its commercial use.[3] In order to address this issue, we report on the condensation of the phenolic ether 1,3,5-trimethoxybenzene (TMB) with formaldehyde (F) yielding inherently hydrophobic aerogels. Suitable synthetic conditions, as well as investigations on structure and wetting properties of the aerogels are presented. [1]: L. Ratke, P. Gurikov, The Chemistry and Physics of Aerogels: Synthesis, Processing, and Properties, Cambridge University Press, Cambridge, 2021. [2]: a) R. W. Pekala, J. Mater. Sci. 1989, 24, 3221-3227. b) S. Mulik, C. Sotiriou-Leventis, N. Leventis, Chem. Mater. 2007, 19, 6138-6144. c) A. M. ElKhatat, S. A. Al-Muhtaseb, Adv. Mater. 2011, 23, 2887-2903. [3]: A. V. Rao, G. M. Pajonk, D. Y. Nadargi, M. M. Koebel, in Aerogels Handbook (Eds.: M. A. Aegerter, N. Leventis, M. M. Koebel), Springer New York, New York, NY, 2011, pp. 79-101.