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Abstract:
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Polycarbonate track -etched membranes (PCTE ) of 50nm and 100nm pore size , precoated with Poly Vinyl Pyrrolidone (PVP ) , were surface treated with either Vinyl Acetic acid (VAA ) or Perfluorohexane (C6F14 ) using a low duty cycle pulsed plasma polymerization technique . The effects of this surface treatment on gas permeation properties of the PCTE were addressed . Plasma coating thickness was controllably varied and resulted in gradual reduction of O2 and CO2 permeability as thickness increased from 10nm to 100nm . Plasma coating material , permeant gas , membrane pore size , and crosslink density were also varied in order to gain insight into the permeation properties of the PCTE . The results show the wide range of permeability achievable via this method . O2 was more permeable than CO2 as expected . Varying the crosslink density had a noticeable effect on the gas permeability as well as the surface wettability . Also , the results from advancing /receding contact angle measurements indicate a much more hydrophobic character when the surface was coated with C6F14 compared to the uncoated and VAA coated samples .
Blood oxygenation is an intended future application of this process . It was shown that the modified PCTE membranes had sufficient O2 and CO2 transfer for this purpose . This study supports the idea of utilizing the plasma polymerization process to modulate the gas permeability characteristics of the PCTE membranes and also alter the membrane surface to improve performance . |