Polymer Swelling studies

A master list of solubility parameters for 166 resins and polymers is shown in Table 5.1. These values were derived from solubility studies, polymer swelling studies and estimated using the group contribution theory. This list is also contained in the spreadsheet data files discussed in Chapter 19. These values can be used to calculate the solvent-polymer radius of interaction values using Equation 5.1. 

The correct choice of solvents is essential to the success of radiation-induced graft copolymerization. Their influence on radiation grafting has been the subject of many studies. It has been established that solvents play an important role in grafting because of the significance of polymer swelling. The grafting patterns to PP are solvent-dependent, thus, it is essential to examine the role of solvents. It was found that grafting in the alcohol is better than when other polar solvents such as dimethyl-... 

Puskas, J.E. Dendritic (arborescent) pol3tisobutylene-polystyrene block copolymers DMTA analysis and swelling studies, Polym. Mater. Sci. Eng., 91, 875-876, 2004. 

Poly(methyl methacrylate) [PMMA] is an excellent polymer for studying photoresist dissolution because of its minimal swelling characteristic. For this work, PMMA molecules were labelled with phenanthrene (Phe) dye since its fluorescence is quenched by MEK. In addition, this dye has the advantage of forming few excimers (23-241 which results in self-quenching. Thus, the reduction in fluorescence intensity of PMMA-Phe is virtually solely due to MEK quenching. Consequently, the permeation of MEK into a PMMA film can be monitored from fluorescence intensity decay. 

Gebel, G., Aldebert, P. and Pineri, M. 1993. Swelling study of perfluorosulpho-nated ionomer membranes. Polymer 34 333-339. 

Ion selective membranes are the active, chemically selective component of many potentiometric ion sensors (7). They have been most successfully used with solution contacts on both sides of the membrane, and have been found to perform less satisfactorily when a solid state contact is made to one face. One approach that has been used to improve the lifetime of solid state devices coated with membranes has been to improve the adhesion of the film on the solid substrate (2-5). However, our results with this approach for plasticized polyvinylchloride (PVC) based membranes suggested it is important to understand the basic phenomena occurring inside these membranes in terms of solvent uptake, ion transport and membrane stress (4,6). We have previously reported on the design of an optical instrument that allows the concentration profiles inside PVC based ion sensitive membranes to be determined (7). In that study it was shown that water uptake occurs in two steps. A more detailed study of water transport has been undertaken since water is believed to play an important role in such membranes, but its exact function is poorly understood, and the quantitative data available on water in PVC membranes is not in good agreement (8-10). One key problem is to develop an understanding of the role of water uptake in polymer swelling and internal stress, since these factors appear to be related to the rapid failure of membranes on solid substrates. 

Studies on glucose-induced polymer swelling have focussed on developing membranes that could serve in systems for controlled delivery of insulin to diabetics (3,4). It has been shown that hydrophobic methacrylate copolymers undergo a sharp swelling transition as the pH is decreased from 7 to 6 (3-7). However, the kinetics of the transition are too slow for the proposed application to glucose delivery. 

It must be concluded, therefore, that none of the above available methods is suited to serve as a standard protocol for an analytical study of polymer swelling. Fortunately, a convenient, easy to use, very reliable method and reproducible for measuring polymer swelling has been developed in the 3M laboratories as an offshoot of a product-oriented research effort. This method is discussed in the following section. 

The value of can thus be determined very accurately on the basis of C using Eq. 44, and considerably less accurately by the volume retention method using chromatography [43]. The values calculated from the values of C determined thus far in ongoing studies of polymer swelling at 3M are reported in Tables 2 17, along with the corresponding 8 values for sake of comparison. 

Chomakova-Haefke, M. Nyffenegger, R. Schmidt, E. Structure reorganization in polymer films of Nation due to swelling studied by scanning force microscopy. Appl. Phys. A 1994, 49. 

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