폴리스티렌 막(polystyrene membrane, PS)의 표면을 Ar, O2 플라즈마로 처리하고, 처리 전후의 변화를 관찰하였고, CO2, N2의 투과도와 N2에 대한 CO2의 선택도는 연속흐름 기체 투과 분석장치(GPA)를 이용하여 측정하였다. Ar플라즈마 처리의 경우 O/C비율이 0에서 0.179로 증가하고, 표면 거칠기가 15.86 Å에서 71.64 Å로 증가함으로써 접촉각은 처리전의 89.16°에서 18.1°로 감소하였다. 따라서 플라즈마 처리는 막표면을 높은 친수성을 갖도록 만들었다. CO2의 투과도와 선택도에 대한 Ar플라즈마 처리최적조건은 60W, 2 min, 70 °C이며, 투과도와 선택도는 각각 2.1×10^-12[m3(STP)·m/m2·sec·atm]와 4.51이었다. O2플라즈마 처리의 경우에, 접촉각은 O/C비율(0.189)과 표면 거칠기(57.10 Å)의 증가에 의해 13.56°로 감소하였다. 최적의 처리조건은 90W-2 min-70 °C이며, 값 7.1×10^-12[m3(STP) · m/m2 · sec · bar]와 값 11.5이었다. 플라즈마 처리 후 막 표면의 변화는 표면에서의 교차결합과 식각효과의 경쟁적인 관계에 의해 결정된다. 결국 플라즈마 처리된 막의 투과도와 선택도가 플라즈마 기체, 처리시간, 출력세기등과 같은 플라즈마 상태를 제어함으로써 향상되었음을 확인할 수 있었다.

The surface of polystyrene membrane treated by Ar, O2 plasma, and the effects were observed before and after the treatment and permeability of CO2, N2 and selectivity of CO2 relative to N2 was measured using continuous flow gas permeation analyzer (GPA). The mole ratio of O over C in the surface was increased from 0 to 0.179 with Ar plasma treatment and route mean square of surface was increased from 15.86 Å to 71.64 Å. Therefore the contact angle was decreased from 89.16° to 18.1°. Thus Plasma treatments made surface of membrane tend to be highly hydrophilic. The optimum condition for the CO2 permeability and ideal selectivity of the plasma treated membrane was as follows: the measurement of Ar (60 W, 2 min, 70 °C) plasma treatment was 1.14×10^-12[m3(STP)·m/m2·sec·atm] and 4.22. In the case of O2 plasma treatment, the contact angle was decreased at 13.56° with increase of O/C ratio (0.189 Å) and route mean square of surface (57.10 Å). The optimum condition for the CO2 permeability and ideal selectivity of the plasma treated membrane was as follows: the measurement of O2 (90W, 2 min, 70°C) plasma treatment was 7.1×10^-12[m3(STP) · m/m2·sec · atm] and 11.5. After plasma treatment, the changes of membrane surface were all subtly linked with both cross-linking and etching effects. Finally, it was confirmed that the gas permeation capacity and selectivity of the modified membrane with plasma could be improved by an appropriate control of the plasma conditions such as treatment time, the power input and sort of plasma gas.

Polystyrene Plasma Treatment Permeation Selectivity

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