N.m.r. imaging of the diffusion of water into poly(tetrahydrofurfuryl methacrylate- co-hydroxyethyl methacrylate)

• Published in: Polymer (Guilford) 1997-07, Vol.38 (15), p.3985-3989
• Main Authors: Ghi, P.Y., Hill, D.J.T., Maillet, D., Whittaker, A.K.
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Fickian diffusion; methacrylate polymers; Miscellaneous; n.m.r. imaging; Organic polymers; Physicochemistry of polymers; Properties and characterization
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/S0032-3861(96)01071-3

Nuclear magnetic resonance (n.m.r.) imaging was used to study the ingress of water into poly(tetrahydrofurfuryl methacrylate- co-hydroxyethyl methacrylate). The study offers strong evidence that the diffusion is Fickian in nature. The diffusion coefficient, D, obtained by fitting the underlying diffusion profile, attainable from the images, according to the equation for Fickian diffusion, is 1.5 × 10 −11 m 2 s −1, which is in good correlation with the value of 2.1 × 10 −11 m 2 s −1, obtained from mass uptake measurements. Additionally, from the T 2-weighted images, superimposed features observed in addition to the underlying Fickian diffusion profiles were shown to have a longer spin-spin relaxation time, T 2. This suggests the presence of two types of water within the polymer matrix; a less mobile phase of absorbed water that is interacting strongly with the polymer matrix and a more mobile phase of absorbed water residing within the cracks observed in the environmental scanning electron micrograph.