Matrix phase swelling

The Nernst-Planck model is based on limiting laws for ideal systems. It accounts only for diffusion and electric transference of ions, not for electroosmotic solvent transfer in the ion-exchanger phase, swelling or shrinking of the ion-exchange material, variations of activity coefficients and diffu-sivities, and possible slow structural relaxation of the exchanger matrix. It also postulates the existence of individual diffusion coefficients for ions. 

Fig. 15 Representation of the optimized system. Cellulose caihanilates are used as long mesogens [112], They form a lyotropic cholesteric phase in mono- and bis-aaylales as solvents. Their photochemical polymerization freezes the helical cholesteric structure. Later on, fluorescent materials can be incorporated into this matrix by swelling and deswelling...

Solution swelling High Vf since no additional matrix required no matrix distribution problems Low risk of relaxation of reinforcement Use of only one polymer type eases recycling Good fibre-matrix continuity matrix phase is sourced fi om surface of reinforcement Can be applied to commodity commercial polymer fibres or fabrics Difficult to control degree of solution swelling Relatively difficult to apply industrially... 

The chemical infusion process was first developed to smooth the surfaces of PMMA rod for use as mandrels for physical vapor deposition of thin metal foils. This technique requires selection of an appropriate solvent for the polymer to act as the solvent component. A second solvent is chosen as a poor solvent for the polymer and will be referred to as the non-solvent component. The non-solvent component must be miscible with the solvent and any additives must be initially soluble in the solvent/non-solvent mixture. This starting solution causes the polymer matrix to swell and, thereby, facilitates the diffusion of the insoluble additives into the treated sector. As the infusion process proceeds, the initial solution is gradually replaced with the non-solvent mixture until the solution consists of greater than 95% diluent. During this latter phase of the process, the solvent diffuses out of the polymer, which results in the restoration of the polymer s surface rigidity. At the end of the process, the polymer samples are removed from the bath, rinsed with the non-solvent to remove additives adsorbed on the surface, and allowed to dry. 

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