Spin probe interaction and mobility in confined cyclohexane: Effects of pore size and pore surface composition of silica gel matrices

[Display omitted] •Spin probe in bulk and confined states of cyclohydrocarbon in various silica gels.•Spectra of spin probe in cyclohydrocarbon depends on composition of silica gels.•Spectral changes are related to phase ones in bulk and confined cyclohydrocarbon. The spectral behavior of the spin probe TEMPO in the bulk cyclohexane (CHX) and its confined states in a series of silica gels (SG) using ESR is reported. The spectral parameter Azz’ and the characteristic ESR temperature T50G of slow to fast regime transition of TEMPO change dramatically in the virgin SG-SIL‘s compared to the bulk CHX sligtly depending on the pore size. These observations result from the interrelation between the mutual interaction of the TEMPO with the SG‘s and the altered phase behavior of the CHX from DSC. This is supported by the modified (silanized) SG matrices.