Polysilsesquioxane Spherical Particles: Synthesis And Property Studies

Polysilsesquioxane (PSQ) particles have been in the limelight owing to their myriad of attractive properties such as excellent thermostability, hydrophobicity and biocompatibility. Such advantageous properties make PSQ particles an equally wide range of applications, including plastic, rubber, coating and biomedicine. PSQ particles have been prepared by sol-gel method, with some general disadvantages, such as complex steps involved and imprecisely controllable sizes. In the present study, a simple and convenient one-pot approach for synthesizing monodisperse PSQ spherical particles with controllable sizes is designed, including polymethylsilsesquioxane (PMSQ) and polyvinylsilsesquioxane (PVSQ). And the influence of PSQ particles as fillers on the thermostability of resin and the surface wettability of coating has been exploringly researched for the first time.(1) In aqueous solution, monodisperse polysilsesquioxane (PSQ) spherical particles have been synthesized in the presence of methyltrimethoxysilane (MTMS) or vinyltriethoxysilane (VTES) as the sole precursor and sodium hydroxide as the catalyst via a one-pot sol-gel technique. The influence of experiment parameters on PSQ particles diameter has been studied. The results reveal that adjusting the concentration of the precursor, the amount of sodium hydroxide or reaction temperature results in the regular tendency of average particle size. Moreover, under the same preparation condition, the diameter of PVSQ particles is less than that of PMSQ particles.(2) The influence of the PSQ particles amount on the thermostability of acrylic resin, which was treated with thermostable PSQ particles, has been investigated. The results show that the thermostability of resin can be enhanced with the increasing amount of PSQ particles. Furthermore, the improvement of PVSQ particles on the thermostability of resin is better than that of PMSQ particles, with the same condition.(3) The surface of thin film consisting of PSQ particles exhibits excellent hydrophobicity, and the water contact angles of PMSQ and PVSQ are 151.4° and 115.2°, respectively. Additionally, the acrylic resin and coating have been treated with the hydrophobic PSQ particles, and then the influence of particles on the microstructure and surface wettability of the corresponding coatings has been analyzed. It is turned out that the coatings possess micro-nano layered structure by adding PSQ particles. Both the rough structure and the hydrophobicity with PSQ particles make the surface converted from origin hydrophilicity to hydrophobicity, overcoming defects existing during coating preparation with PSQ as common film-forming material. And by comparision, hydrophobic modification of PVSQ particles on the coatings is weaker than that of PMSQ particles with the same condition.