Interfacial behavior of polar and nonpolar frozen/unfrozen liquids interacting with hydrophilic and hydrophobic nanosilicas alone and in blends.

Hypothesis: Various nanosilica characteristics depend on hydrophobization strongly affecting interfacial phenomena. Is it possible to prepare hydrophilic samples with hydrophobic silica (AM1) alone and in blends with hydrophilic one (A-300)? It can be done with addition of a small amount of water to the powders which then are mechanically treated.

Experiments: Nanosilicas were characterized using adsorption, desorption, microscopic, spectroscopic, and quantum chemistry methods.

Nanosized copper(ii) oxide/silica for catalytic generation of nitric oxide from S-nitrosothiols.

Nitric oxide NO, mediates inflammatory and thrombotic processes and designing biomaterials capable of releasing NO in contact with biological tissues is considered to be a major factor aimed at improving their bio- and haemocompatibility and antibacterial properties. Their NO-releasing capacity however is limited by the amount of the NO-containing substance incorporated in the bulk or immobilised on the surface of a biomaterial. An alternative approach is based on the design of a material generating nitric oxide from endogenous NO bearing metabolites by their catalytic decomposition.

Polymethylsiloxane alone and in composition with nanosilica under various conditions.

Disperse polymethylsiloxane (PMS) alone and in a mixture with highly disperse nanosilica A-300 was studied as a dry powder and a hydrogel located in various dispersion media (air, chloroform alone and with addition of trifluoroacetic acid) using low-temperature H NMR spectroscopy, cryoporometry, thermogravimetry, nitrogen adsorption, microscopy, infrared spectroscopy, and quantum chemistry. The powders of dried PMS and PMS/A-300 can be easily rehydrated upon strong stirring with added water. The slurry properties depend on mechanical treatment features due to stronger compaction of the secondary structures with increasing mechanical loading.

Water Interactions with Hydrophobic versus Hydrophilic Nanosilica.

It is well-known that interaction of hydrophobic powders with water is weak, and upon mixing, they typically form separated phases. Preparation of hydrophobic nanosilica AM1 with a relatively large content of bound water with no formation of separated phases was the aim of this study. Unmodified nanosilica A-300 and initial AM1 (A-300 completely hydrophobized by dimethyldichlorosilane), compacted A-300 (cA-300), and compacted AM1 (cAM1) containing 50-58 wt % of bound water were studied using low-temperature H NMR spectroscopy, thermogravimetry, infrared spectroscopy, microscopy, small-angle X-ray scattering, nitrogen adsorption, and theoretical modeling.