The Effect of Polymethylsilsesquioxane Concentration on the Liquid Foundation: Characterization of Nanostructure and Biophysical Properties

Aims: Polymethylsilsesquioxane (PMQS) is a silicone derivative that serves as a skin conditioning agent and moisturizer in cosmetics. The objective of this study is to identify the effect of different concentrations PMSQ (0.12, 0.20 and 0.35 wt %) on liquid foundation (LF) and find the optimized composition in vitro. Study Design:  Structural and morphological features of the examined nano/micro-sized samples were investigated by different methods. Place and Duration of Study: Hacettepe University, Department of Physics Engineering, X-Rays Laboratory, between September 2017 and September 2019. Methodology: Micro/nano scale structural and morphological properties of samples were investigated by means of a multi-methodological approach based on Small‐ and/or Wide‐Angle X‐ray Scattering (SWAXS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDX), Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) Spectroscopy and UV-vis Spectroscopy.  The LF (control) and PMSQ-LF films at one-week intervals for 4 weeks, and bovine leather coated samples with LF and PMSQ-LF were also investigated by SWAXS.   The effect of PMSQ on biofilm formation activity in E. coli and S. aureus were also examined. Results: The most significant finding of this study is that even the low concentration of polymer in LF showed differences in nano structure and it was found that a decrease in biofilm formation. Nano formation becomes more pronounced, and the number of agglomerations decreases after 4 weeks. The reason for the study over a 4-week period was the desire to take into account the independent effect of each LF use, as well as the periodic stacking and diffusing effect that will occur in the depths of the skin over time. In the UVA range (320-400 nm) lower transmittance values were found for LF and PMSQ - LF films.   Conclusion: The results suggest that optimum polymer concentration in liquid foundation should be considered as a main step. The smart and systematic use of polymer additives is directly manifested in the nanoscopic structure and can improve the harmful UV rays prevention properties, which are important for health as well as cosmetic effects for beauty purposes.