Репозиторий Университета

© 2020 Elsevier Ltd A laser technology has been developed for fabricating structures from composite layers based on biopolymers: albumin, collagen, and chitosan with single-walled carbon nanotubes (SWCNT). The structures are intended for cardiovascular devices and tissue-engineered implants. This is evidenced by the results of studies. The composite layers were fabricated due to the phase transition of biopolymers and SWCNT aqueous dispersion under the influence of laser pulses. At the same time branched 3D networks of SWCNT were formed in the biopolymer matrix. The threshold energy fluence of laser pulses was determined (0.032–0.083 J/cm2) at which a bimodal distribution of pores was observed. The calculation of contact resistances between nanotubes at percolation units of 3D networks (20–100 kOhm) was carried out. Composite layers fabricated by laser demonstrated conductivity values that were higher (12.4 S/m) than those for layers by thermostat (4.7 S/m). The maximum hardness of the composite layers with SWCNT (0.01 wt%) by laser was 482 ± 10, 425 ± 10, and 407 ± 15 MPa for albumin, collagen and chitosan, respectively. The hardness of the thermostat layers was less than 100 MPa. The viability of endothelial cells in composite layers was improved. The composite layers ensured a normal level of hemolysis during interaction with erythrocytes.

© 2018, Peter the Great St. Petersburg Polytechnic University. Nanocomposite layers consisting of an acrylic paint and single-walled carbon nanotubes (∼1.5 wt.%) have been investigated. The investigated samples had a disk shape with a diameter of 20-30 mm and a thickness of 2-50 μm. After exposure in water for 350 h, the layer mass remained almost invariable (a mass loss of ≤ 1.5%) and the layer samples exhibited high adhesion to glass substrates and a conductivity of ∼ 40 S/m. The layers consisting of the nanotubes and acrylic paint exfoliated from the substrates for ∼1 h. After heat treatment at a temperature of 140 °C, all the layers exhibited a semiconductor-type temperature dependence of the resistance. The prospects of using these layers in various medical products, e.g. implants for wireless energy transmission, have been discussed.