No abstract

Switchable surfaces were fabricated by grafting of two different polymers: polystyrene (PS) and poly-2-vinylpyridine (PVP) onto the surface of Si-wafers. The binary brushes of various composition, molecular weight and grafting density were synthesized via free radical polymerization initiated by the azo-initiator covalently attached to the surface of Si-wafers. Investigations showed that the binary brushes are very sensitive to the surrounding media. After exposition to a solvent selective for PVP (ethanol, water + HCl) the surface becomes hydrophilic and the top of the layer is covered by PVP. After exposition to a solvent selective for PS (toluene) the surface becomes hydrophobic and the top of the layer is enriched with PS segments. Switching kinetics depends on grafting density and layer composition and varies from several seconds to several minutes at room temperature. Surface morphology of the layers switches as well as the wetting behavior. Results show that the layer reconstruction is reversible and can be repeated many times.

Electrochemical defense by cathode polarization together with isolating coverage − for today is most effective from all methods of fight against corrosion. Essence of electrochemical defense consists in deceleration of corrosive processes, mainly electrochemical. Cathode defense − conducted by means of direct-current from outsourcing at that object that is subject to defense joins negative to the pole of the station of cathode defense (in quality to the cathode), and the sacrificial anode of grounding joins in with a positive pole. Setting of cathode defense is building which is used for cathode polarization of pipeline by an external current. By settings of cathode defense (UKZ) which polarizes a pipeline, corrosive processes are taken to the minimum value or quite halted. A surface of pipeline is in defense and does not collapse in an aggressive environment during great while or destructive processes are taken to the minimum values. The structural changes of metal and changes of mechanical descriptions of the steel anodic grounding conditioned to these, stations of cathode defense, made from material of Stal'20 Du159, were investigated in our work.