Sketch of the samples. (a) A schematic view of the porous Si nanoparticle (PSiNP) coating process where brown color corresponds to silicon, violet to PLGA, green to PVA and light blue to water. Note that every PSiNP includes several smaller nanocrystals (nc-Si). (b) Magnification of the uncoated PSiNP surface contiguous to liquid water. Hydrophobic surface mostly consisted of Si-H bonds was colored black and hydrophilic one mostly consisted of Si-O bonds was colored yellow. (c) Magnification of the coated PSiNP surface. Violet and green lines correspond to PLGA and PVA molecules. Note that liquid water is not in direct contact with the silicon surface of PSiNPs due to the hydrophobic properties of PLGA.
Gongalsky et al. Nanoscale Research Letters 2012 7:446 doi:10.1186/1556-276X-7-446