Gelation Process of Toluene-Based bis-Urea in Cyclohexane Studied with Magnetic Resonance Imaging

J. Tritt-Goca, J. Boguszyńskaa, M. Szwaja, L. Boutellierb and J. Jadżyna aInstitute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland bLaboratoire de Chimie des Polyméres, UMR 7610, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris CEDEX 05, France

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Received: 24 04 2005;

Magnetic resonance imaging was used for studies of the gelation and swelling processes of toluene-based bis-urea prepared in a form of cylindrical tablet and immersed in cyclohexane. The processes were investigated with the use of Bruker AVANCE (300 MHz) spectrometer equipped with a micro imaging probe head. The images were taken for cyclohexane protons within the bis-urea gel formed around the sample dry core at different intervals of the immersion. The mobility of the solvent molecules was estimated from the spatially resolved distribution of the spin-spin relaxation time T2 and the spin densities ρ, calculated on the basis of the images obtained. It was shown that the time-evolution of the thickness of the gel layer can be well described by the power equation with an exponent equal to 0.47 (±0.04), indicating the Fickian nature of the diffusion of cyclohexane molecules.

DOI: 10.12693/APhysPolA.108.81 PACS numbers:82.70.Gg, 76.60.Pc, 82.56.Lz, 82.56.Na