OH groups, dangling

Although it was postulated earlier that silane monolayers covalently bound to substrates possessing dangling OH groups could be formed by the... 

F igure 15.1. A schematic representation of a reaction at an oil-water interface. The transition state (AB ) is stabiUzed through the formation of strong HBs offered from the free dangling -OH groups. Here the transition state becomes more stabilized than the reactants. Adapted with permission from J. Am. Chem. Soc., 129 (2007), 5492-5502. Copyright (2007) American Chemical Society. 

C. S. Hsieh, R. K. Campen, A. C. V. Verde, P. Bolhuis, H. K. Nienhuys, and M. Bonn, Phys. Rev. Lett., 107,116102 (2011). Ultrafast Reorientation of Dangling OH Groups at the Air-Water Interface Using Femtosecond Vibrational Spectroscopy. 

Their implication in the synthesis of linear PU using an aliphatic diisocyanate produced materials with a Tg below RT, in part because of the flexibility of both monomer units and, additionally, because of the dangling chains in some of the diester diols. Given that these monomers bore one or two secondary OH groups, polymerisations were rather slack and the ensuing molecular weight relatively low. 

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