Journal of Physical Chemistry B, Vol.117, No.35, 10311-10319, 2013
Molar Volumes of Ethylcyclohexane and Butyronitrile Glasses Resulting from Vapor Deposition: Dependence on Deposition Temperature and Comparison to Alkylbenzenes
Molar volumes (V-m) of vapor-deposited ethylcyclohexane (ECH) and butyronitrile (BN, sometimes called butanenitrile) glasses were studied as a function of deposition temperature (T-d). ECH glasses deposited at T-d sufficiently, below their. glass transition temperature (T-g) exhibited changes in V-m on heating similarly to alkylbenzenes. At T-d close to T-g, ECH formed dense glasses at alkylbenzenes do, although these glasses were Only slightly more dense than its supercooled liquid (SCL) states at the same temperatures For BN, no indication of the formation of dense glasses was observed even at T-d close to T-g, and the variations in V-m with the temperature elevation Were different from those of alkylbenzenes. Analysis of the initial V-m of the deposited glasses of different compounds demonstrated that its T-d-dependence was well. correlated With the steepness index (m) of the corresponding SCL. Quantum chemical concerning dimer formation by the studied compounds showed that the hydrogen bond between a C-H bond in the alkyl group and pi-electrons in the phenyl ring stabilizes the.; alkylbenzene dimers, suggesting the passibility of the dense glass formation and large m of these compounds. The small M value of BN was also discussed On the basis Of the calculation results.