Membranes intermediate hydrogel

The partition coefficients for water in p-HEMA and p-HEMA crosslinked with 1 mole % EGDMA are 0.52 and 0.51 respectively. However, from Sung s data (5), it is possible to define partition coefficients for water into the various subclasses of water in the hydrogel membranes. For p-HEMA, these values of Ko are bulk water 0.30, bulk + intermediate water 0.41, and bulk + intermediate + bound water 0.52. For p-HEMA with 1 mole % EGDMA, the values are bulk water 0.21, bulk + intermediate water 0.36, and bulk + intermediate + bound water 0.50. A comparison of these values with the experimental values found in Tables I and II indicates that the sugars partition primarily into bulk water of both membranes and, therefore, that the diffusion of these solutes occurs primarily in the bulk water of the membranes. This result is consistent with the observed very low permeability of inositol and raffinose in p-HEMA with 5 mole % EGDMA. These membranes have 1 i ttl e or no bul k water (5.). 

We have emphasized here that the dynamic aspects of NMR studies are crucially important for structurally or dynamically heterogeneous systems such as synthetic or natural hydrogels, protein fibrils and membrane proteins. This is in order to characterize their unique chemical, physical and biological properties in terms of a variety of fluctuation frequencies, including high (> 108 Hz) or intermediate (104-105 Hz) frequency fluctuations. It turns out that the presence of the high-frequency motions, which are readily evaluated by comparative CPMAS and DDMAS studies, is... 

When the conducting polymer is used as ion-to-electron transducer in the form of an intermediate layer between the electronic conductor and the ion-selective membrane it does not significantly influence the sensitivity and selectivity of the ISE, but it allows high potential stability [75]. For example, microfabricated solid-state K+-ISEs with polypyrrole as ion-to-electron transducer was found to show even better long-term potential stability than those based on a hydrogel contact [58]. The potential of the polypyrrole-based K+-ISE was slightly more sensitive to the oxygen concentration of the sample in comparison to... 

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