Endowment of Improved Mechanical Properties for Polyhedraloligomericsilsesquioxane Coatings through a Dynamic Regulation Method

Polyhedral oligomeric silsesquioxane (POSS) coatings are known for their high hardness, wear resistance, and transparency. While modifying the organic substituents can tailor certain properties, the influence of the inorganic core’s size on mechanical performance remains unclear, and methods to control it are lacking. This study introduces a dynamic regulation strategy to precisely control POSS particle size and systematically investigates its impact on the properties of cured coatings. By employing a reaction-controlled condensation process─modulating temperature, rotation speed, and final concentration to remove byproducts─we produced POSS particles four times larger than those from uncontrolled reactions. The mechanical properties of the cured coatings were strongly proportional to the particle size. The optimized coating achieved a hardness of 0.462 GPa and a modulus of 17.008 GPa, significantly higher than the values for the uncontrolled sample (0.214 and 3.174 GPa, respectively). Furthermore, the coating exhibited excellent wear resistance, withstanding 10,000 cycles of steel wool abrasion under 12.5 kPa pressure without visible scratches. Critically, this method is also applicable to other raw materials, including hydrophobic and UV-curable variants. This work provides a versatile strategy for fabricating high-performance, hard, and flexible coatings with customizable properties.