Methacrylic hydrogels, surface properties

However, the increase in resistance with decreasing water vapor pressure in the present case appears to be a new clue and has been useful in at least arguing against some possible mechanisms. It appears feasible that the surface properties of the film are changing in response to the external environment, specifically the relative humidity. There is evidence that a surface of a methacrylate hydrogel is more hydrophobic in air saturated with water vapor than in liquid water [28]. If we assume that ionomers show a similar behavior, and that the surface becomes still more hydrophobic at lower humidities, then greater resistance to water sorption could result, thus explaining the observed results. 

To end, we must emphasize that methacrylates in medicine are made use of in diverse areas including bone and dental cements (109), and as surface modifiers to prevent or delay process of rejection (110), and that each commands a formidable literature. The reader should also be aware of the considerable effort which has been directed towards a phenomenological and theoretical understanding of the solution and swelling properties of synthetic hydrogel and polyelectrolyte polymers (111-116). 

It would be of interest to add some functionalities such as properties in response to changes in pH, temperature, electrical potential and so on as well as hydrophilic properties to PTFE surfaces by the combined technique just described. Poly(AT-isopropylaoylamide) (PNIPA ) is a well-known thermo-responsive polymer whose hydrogel undergoes a volume change around 31 C in an aqueous solution. And further, poly 2-(dimethylamino)ethyl methacrylate (PDMA) in a pH 10 buffer solution exhibits a drastic decrease in the transmittance around 28 °C, which is considered to come from a phase transition of PDMA chains (ii). Therefore, we have tried to prepare JV -isopropylacrylamide (NIPAAm) or 2-(dimethylamino)ethyl... 

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