고분자-불소계면활성제 복합체와 실리카 나노입자를 이용한 다층박막의 젖음성에 관한 연구 = Wetting Properties of Layer-by-Layer Films of Polymer-Fluorinated Surfactant Complex and Silica Nanoparticles

다국어 초록 (Multilingual Abstract)

Recently, there has been increasing interest in the hydrophilic/oleophobic surface that can be applied for self-cleaning and oil-repellent anti-fogging coatings. This surface shows a low water contact angle (WCA) and a high optical contact angle (OCA), unlike conventional surfaces. In this study, a layer-by-layer (LbL) assembly technique is used to fabricate a surface that has a higher OCA value than WCA. A poly(allylamine hydrochloride) (PAH)-sodium perfluorooctanoate (SPFOA) complex and silica nanoparticles were used to build LbL films. The effect of LbL assembly on the contact angle was studied. When the pH of the PAH-SPFOA solution was 6.5 and 7.5, the WCA/OCA of the LbL films with a PAH-SPFOA outermost layer were 53°/0° and 80°/0°, respectively. In contrast, at a pH of 9.0 in the PAH-SPFOA solution, the WCA and OCA were 127° and 89°, respectively. When films assembled using PAH-PFOA with a pH of 6.5 and 7.5 were additionally treated with SPFOA, WCA/OCA were 79°/66° and 98°/81°, respectively. When LbL films with a silica nanoparticle-terminated layer were treated with SPFOA, WCA/OCA changed from 81°/57° to 89°/88°, where the WCA and OCA values became most similar. The effect of silica nanoparticle sizes of 7 nm to 22nm on the WCA/OCA difference was negligible. Although hydrophilicity/oleophobicity of the LbL film was insufficient, the results will serve as the basis for research on LbL-assembled hydrophilic/oleophobic surfaces.

국문 초록 (Abstract)

최근 들어 자가세정, 발유성 김서림 방지 코팅 등으로 응용 가능한 친수/발유성 표면에 대한 관심이 증가하고 있다. 친수/발유성 표면은 일반적 표면과 달리 물 접촉각이 작고, 오일 접촉각이 큰 특수한 표면이다. 본 연구에서는 친환경적인 다층박막적층법을 이용하여 물 접촉각보다 오일 접촉각이 더 큰 표면을 구현하고자 하였다. Poly (allylamine hydrochloride) (PAH)-sodium perfluorooctanoate (SPFOA) 복합체와 실리카 나노입자를 이용하여 다층박막을 제조하였다. 다층박막 어셈블리 조건에 따른 접촉각의 변화를 관찰하였다. PAH-SPFOA 용액의 pH가 6.5, 7.5인 경우, 최외각층이 PAH-SPFOA인 다층박막의 물/오일 접촉각은 53°/0°, 80°/0°이었다. 반면 PAH-SPFOA 용액이 pH 9.0인 경우, 물/오일 접촉각이 127°/89°로 증가하였다. pH 6.5, 7.5의 PAH-SPFOA 용액으로 제조한 다층박막을 SPFOA로 추가적으로 표면 처리한 경우, 물/오일 접촉각은 79°/66°, 98°/81°이었다. 실리카 나노입자가 최외각층인 다층박막은 SPFOA 표면처리를 통해, 물/오일 접촉각이 81°/57°에서 89°/88° 변화하여, 물/오일 접촉각의 차이가 가장 작게 나타났다. 7 nm와 22 nm의 실리카 나노입자 크기 차이는 물/오일 접촉각 차이에 큰 영향을 미치지 못하였다. 실험결과 다층박막의 친수/발유성이 미흡하나, 다층박막법을 이용한 친수/발유성 표면 연구에 기초가 될 것으로 기대한다.

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