Here, we prepared hydrophilic/oleophobic layer-by-layer (LbL) assembled films. Polyethyleneimine (PEI)/SiO₂ LbL films were prepared. Then PEI was adsorbed onto it, and fluorosurfactant (FS-10) was adsorbed. When the pH of the PEI and FS-10 solution was 10 and 3.5, respectively, adsorption of FS-10 was highest, with a water contact angle (WCA) of 55° and an oil contact angle (OCA) of 87°. When a mixture of FS-10 and SiO₂ solution was adsorbed, as the SiO₂ mixing ratio increased from 0% to 90%, the OCA decrease slightly, while the WCA significantly decreased. When the SiO₂ content was 80%, the WCA was 0° and the OCA was 81°. Surface morphology showed a unique fibrous structure on the fairly smooth LbL film surface. Through control of the surface structure and the chemical composition of the oleophobic FS-10 and hydrophilic SiO₂ nanoparticles, hydrophilicity/oleophobicity was obtained.

본 연구에서는 친수/발유성 다층박막에 관한 연구를 수행하였다. 먼저 poly(ethyleneimine)(PEI)/SiO₂ 다층박막을 제조하고 그 위에 PEI 흡착시킨 후, 불소계면활성제(FS-10)를 흡착시켰다. PEI와 FS-10 용액의 pH가 각각 10과 3.5인 경우, FS-10의 흡착이 가장 높았으며, 물접촉각은 53°, 오일접촉각은 87°이었다. FS-10과 SiO₂ 혼합액을 흡착시킨 경우, SiO₂ 용액의 혼합비율이 0%에서 90%로 증가함에 따라, 오일 접촉각은 소폭 감소하였으나 물접촉각은 크게 감소하였다. SiO₂ 용액의 혼합비율이 90% 일때, 물접촉각은 0°, 오일접촉각은 81°로 나타났다. 표면모폴로지 관찰 결과, 비교적 매끄러운 다층박막 위에 섬유상이 발견되었다. 이러한 표면구조와 발유성의 FS-10 및 친수성의 SiO₂ 나노입자의 화학조성의 조절을 통해 친수/발유성을 구현하였다.

Keywords: layer-by-layer, polyelectrolyte, hydrophilic, oleophobic, wetting.