Modification of TiO2 Nanoparticles with Oleyl Phosphate via Phase Transfer in the Toluene–Water System and Application of Modified Nanoparticles to Cyclo-Olefin-Polymer-Based Organic–Inorganic Hybrid Films Exhibiting High Refractive Indices

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• 作者：Shiori Takahashi ; Shuhei Hotta ; Akira Watanabe ; Naokazu IdotaKimihiro Matsukawa ; Yoshiyuki Sugahara
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：9
• 期：2
• 页码：1907-1912
• 全文大小：410K
• ISSN：1944-8252

文摘

Oleyl-phosphate-modified TiO₂ nanoparticles (OP_TiO₂) were prepared via phase transfer from an aqueous phase containing dispersed TiO₂ nanoparticles to a toluene phase containing oleyl phosphate (OP, a mixture of monoester and diester), and employed for the preparation of OP_TiO₂/cyclo-olefin polymer (COP) hybrid films with high-refractive indices. The modification of TiO₂ by OP was essentially completed by reaction at room temperature for 8 h, and essentially all the TiO₂ nanoparticles in the aqueous phase were transferred to the toluene phase. The infrared and solid-state ¹³C cross-polarization and magic-angle spinning (CP/MAS) NMR spectrum of OP_TiO₂ showed the presence of oleyl groups originating from oleyl phosphate. The solid-state ³¹P MAS NMR spectrum of OP_TiO₂ exhibited new signals at −1.4, 2.1, and 4.8 ppm, indicating the formation of Ti–O–P bonds. CHN and inductively coupled plasma analyses revealed that the major species bound to the TiO₂ surface was tridentate CH₃(CH₂)₇CH═CH(CH₂)₈P(OTi)₃. These results clearly indicate that the surfaces of the TiO₂ nanoparticles were modified by OP moieties via phase transfer. OP_TiO₂/COP hybrid films exhibited excellent optical transparency up to 19.1 vol % TiO₂ loading, and the light transmittance of the hybrid films with 19.1 vol % TiO₂ loading was 99.8% at 633 nm. The refractive index of these hybrid films rose to 1.83.