Poly(methyl methacrylate) film dissolution and solvent diffusion coefficients: correlations determined using laser interferometry-fluorescence quenching and pulsed-gradient spin-echo NMR spectroscopy

Abstract

We correlate the results of pulsed-gradient spin-echo (PGSE) nuclear magnetic resonance (NMR) measurements of solvent self-diffusion coefficients in binary poly(methyl methacrylate) (PMMA) mixtures with laser interferometry-fluorescence quenching (LIFQ) measurements of PMMA film dissolution for a series of identical ketone and ester solvents. Within a homologous solvent series, the self-diffusion coefficients as well as film dissolution rates decrease in tandem with increasing solvent molecular size and cross-section. When self-diffusion coefficients are compared, little difference is found between esters and ketones of normally identical molecular size. However, systematic differences in film dissolution rates are evident when comparing ketone and ester solvents. These differences are eliminated when film dissolution rates for esters and ketones are compared on the basis of the solvent free volume parameters extracted from the PGSE NMR self-diffusion coefficient data using Fujita's free volume theory.

Self-Diffusion of Solvents and Solute Probes in Polymer Solutions and Gels: The Use of a New Physical Model of Diffusion

“…The samples for the diffusion studies include binary poly(methyl methacrylate) (PMMA)-organic solvent (30,31) and ternary PVA-water-solute systems (70,22). The PMMA used has a molecular weight of 60,000.…”

“…The preparation of the samples for NMR experiments has been described (10,22,30,31). For the ternary aqueous systems, PVA was dissolved in D 2 0 containing 1 wt% solute probe.…”

“…We have proposed a new physical model for the diffusion of solvent and solute molecules in polymer solutions. By treating the polymer solution as a statistical network through which the solute diffuses in a series of jumps over potential barriers determined by the correlation length, we find that we can describe the diffusion bahavior of both small and large solutes, in both dilute and more concentrated polymer solutions in water and organic solvents (10,22,30,31), and over a range of temperatures.…”

Swelling and dissolution behavior of poly(methyl methacrylate) films in methyl ethyl ketone/methyl alcohol mixtures studied by optical techniques

“…The mean penetration rate dX B /dt was found to be 0.36 Ϯ 0.08 m/min, within the range of 0.16 -0.4 m/min of dissolution rates found by other investigators for the same system. 10,15,16,27,28 The corresponding OPD profile (Fig. 5) indicates the existence of a penetrant precursor front (consisting of the infiltration and solid layers, according to Ueberreiter's 7 terminology) ahead of front B.…”

“…Penetration and dissolution kinetics have been studied by a variety of techniques, such as optical microscopy, 7,12,13 refractometry, 7 laser interferometry, 10,14 -16 ellipsometry, 17,18 critical angle illumination microscopy, 8 and fluorescence methods. 16 Penetrant concentration profiles have been obtained by interferometry, 7,12,13 MRI analysis, 19 fluorescence quenching, 10 Rutherford backscattering, 20 and optical microdensitometry. 12,21 The above-mentioned techniques were applied during transport of solvents 7,8,10,12,13,[15][16][17]19 or nonsolvents [12][13][14]17,18,21 in free films, 7,21 films clamped between glass plates, 12,13 or, finally, in supported films.…”