Improving superhydrophobicity of polydimethylsiloxanes using embedding fluorinated polyhedral oligomeric silsesquioxanes cages

Abstract

Improving the superhydrophobicity of polydimethylsiloxane (PDMS) is a current interest in a wide range of applications from biomedical to aerospace. Although many fabrication techniques are available to improve the superhydrophobicity of PDMS, a significant problem occurs when the fabrication technique applies as a scalable but simple one. Here, we have described simple methods to achieve superhydrophobicity of PDMS using short-chained fluorinated polyhedral oligomeric silsesquioxanes (FPOSS). Two species of FPOSS were incorporated into PDMS using four different methods; non-solvent blending, solvent blending, spraying FPOSS/PDMS solution onto a partially cured PDMS matrix and spraying only FPOSS solution onto partially cured PDMS surfaces. Among two FPOSS species, spraying FPOSS onto partially cured PDMS produced a superhydrophobic surface with a static water contact angle of 167° ± 1°. Trifluoropropylisobutyl POSS (TFP) resulted in a higher hydrophobicity than trifluoropropyl POSS cages (CM). The multi-scale structured surface morphology, compatibility of functional groups attached to FPOSS and the fluorine content have shown a significant contribution on the superhydrophobicity in FPOSS/PDMS systems. Amorphous nature of the PDMS has improved upon incorporating FPOSS. Hence, this work presents a detailed study on the effect of the preparation method of FPOSS/PDMS composite on its superhydrophobicity.