US EPA

3005691 

Journal Article 

Dopant effects on 2-ethyl-1-hexanol: a dual-channel impedance spectroscopy and neutron scattering study 

Singh, LP; Raihane, A; Alba-Simionesco, C; Richert, R 

2015 

Yes 

Journal of Chemical Physics
ISSN: 0021-9606
EISSN: 1089-7690 

142 

1 

014501 

English 

25573566 

10.1063/1.4904908 

WOS:000347973600023 

A two-channel impedance technique has been used to study the relaxation behavior of 2-ethyl-1-hexanol with polar and non-polar dopants at the few percent concentration level over a wide temperature and frequency range. The non-polar dopants shift both the Debye and the primary structural relaxation time in the same direction, to shorter times for 3-methylpentane and to longer times for squalane, consistent with the relative glass transition temperatures (Tg) of the components. By contrast, polar dopants such as water or methanol modify the α-process towards slower dynamics and increased amplitude, while the Debye process is accelerated and with a decreased amplitude. This effect of adding water to alcohol is explained by water promoting more compact structures with reduced Kirkwood correlation factors. This picture is consistent with a shift in the neutron scattering pre-peak to lower scattering vectors and with simulation work on alcohol-water systems.