Surface and confinement effects on the dielectric relaxation of a monohydroxy alcohol

2-ethyl-1-hexanol (2E1H) was confined to the surface of a collagen matrix at various concentration levels c. Dielectric spectroscopy revealed that upon decreasing c, the alcohol's prominent hydrogen-bond mediated Debye-like relaxation broadens and turns nonexponential. This destabilization of the supramolecular association is accompanied by an increasing relative strength of the structural relaxation in 2E1H up to a point beyond which the two processes are merged when the solvent molecules are sufficiently diluted. These results demonstrate that the contribution of the Debye-like relaxation can be completely suppressed and concomitantly the limit of a simple, nonassociating liquid is reached. Confinement of the alcohol in a monolithic glass with nanoscopic pores subjected to different internal surface treatments is also demonstrated to bear a large impact on the relative strengths of the two processes. (C) 2011 American Institute of Physics. [doi:10.1063/1.3655356]