Preparation and Properties of Ultra-Smooth Surfaces of Polyimide Composites

In this paper, TiO₂ particles submicron were prepared by sol-gel method and modified with 3-aminopropyl triethoxysilane (KH550) after coating SiO₂ on its surface. Subsequently, combined with the breath figure method (BF), slippery liquid-infused porous surfaces (SLIPS) of polyimide composites were prepared by a two-step method using TiO₂/SiO₂ particles, amino terminated polysiloxanes (APT-PDMS), 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (BAPP) and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) as the raw materials. The compositions and properties of the composites were characterized by infrared spectroscopy, nuclear magnetic resonance and thermal weight loss, respectively. The apparent morphology of the porous membrane was observed by scanning electron microscopy, and the hydrophobic properties of the porous membrane were investigated before and after the infilling of the silicone oil by contact angle tester. The results show that the hydrophobicity of the porous substrate prepared when the content of TiO₂/SiO₂ particles is 15% and the concentration of composite material is 20 mg/mL is the best, and the sliding angle of the oil-filled SLIPS is 2° at the minimum. The SLIPS owns good stability, self-cleaning, and anti-freezing properties and so on.