Polymethylsilsesquioxane

Kaya, P., et al. Asian Journal of Physical and Chemical Sciences, 2021, 9(4), 32-45.

Polymethylsilsesquioxane (PMQS) serves as a skin conditioning agent and moisturizer in cosmetic products while being a silicone derivative. This work investigated how different PMSQ concentrations (0.12, 0.20 and 0.35 wt%) affected liquid foundations to find the best composition through in vitro analysis.
· Research Methods
SWAXS along with SEM/EDX, ATR-FTIR spectroscopy and UV-visible spectroscopy were utilized to examine the micro/nanoscale structural and morphological properties of the samples. The study also measured how PMSQ influenced biofilm formation in both Escherichia coli and Staphylococcus aureus.
· Findings
Even at a low concentration, polymers in LF demonstrated variations in their nanostructure and were associated with a reduction in biofilm formation. The mixture of LF with 0.20% wt PMSQ displayed strong antimicrobial efficacy toward biofilms formed by E. coli and S. aureus. The nanostructure formation became visibly clearer within a four-week period while agglomerations showed a reduction.
LF films along with PMSQ-LF films exhibited reduced transmittance levels when tested in the UVA range between 320 and 400 nm. Polymer additives strategically incorporated into materials result in substantial changes to their nanoscopic structure which improves their UV blocking capability essential for health-related and cosmetic applications.

Cross, Sheree E., et al. Skin pharmacology and physiology, 2007, 20(3), 148-154.

The extent to which topically applied solid nanoparticles can penetrate the stratum corneum and enter the underlying viable layer of the epidermis and the rest of the body is a significant potential safety concern. This work developed a ZnO sunscreen nanoparticle coated with polymethylsilsesquioxane (PMQS) and investigated the penetration of this zinc oxide sunscreen formulation into the human epidermis to verify the location of the nanoparticles in the exposed membrane.
PMQS-coated ZnO sunscreen formulation
· Particle Manufacturing: ZnO nanoparticles were synthesized using MCP TM technology, which employs high-energy dry milling to facilitate chemical reactions during ball collisions. To reduce agglomeration, particles are encapsulated by a solid diluent phase, usually sodium chloride, during formation. This diluent is later removed through a simple washing process, allowing the nanoparticles to be transferred into the desired oil phases. Subsequently, ZnO particles were coated with polymethylsilsesquioxane. In this process, the nanoparticles were first dispersed in a solvent, to which siliconeate monomers were added. A polymerization initiator was gradually introduced while the mixture was stirred vigorously, resulting in the formation of polymethylsilsesquioxane on the particle surface.
· Formulation Preparation: Three samples were prepared for testing: (i) a ZnO dispersion containing 60 wt% siliconate-coated ZnO in caprylic capric triglyceride, (ii) a standard oil-in-water emulsion sunscreen with 20 wt% ZnO, and (iii) a blank oil-in-water emulsion sunscreen without ZnO.