Hydrolytic conversion of preceramic polymers into silicate glass coatings with different wettability

Abstract

In this paper, two types of preceramic polymers were used to form silicate glass coatings with different wettability via hydrolysis either under harsh or mild conditions. Allylhydridopolycarbosilane (AHPCS) and polyvinylsilazane (PVSZ) were spin-coated on Si substrate and consolidated by photo- and thermal-curing and subjected to hydrolysis for conversion to the silicate glass phase. The contact angle of the both hydrophobic cured polymers decreased from 91°–92° to 18°–36° with little difference, when hydrolyzed in strong alkaline of NaOH solution at room temperature. However, soft hydrolysis in ammonia vapor at 80 °C showed that the AHPCS derived silicate surface showed the moderate contact angle 58°, while the PVSZ derived silicate became very hydrophobic surface with the contact angle 103° presumably due to re-oriented alkyl groups. Eventually, it was demonstrated that the surface wettability of the hydrolyzed silicates was controlled with the polymer chemistry and the hydrolytic conditions upon the preceramic polymer-to-silica conversion.