The electrical conductivity evaluation of nanocoating on intelligent building structure elements

Introduction. Flexible elements made from various materials such as films, papers and geotextiles, coated with an electrically conductive coating containing carbon nanoparticles, have the potential for creating intelligent structures. To rationally choose, design, and apply electrically conducting components, it is necessary to objectively assess their behavior throughout the life cycle of these objects. Currently, there are no objective methods for evaluating such components. Methods and tools are needed that can not only evaluate initial electrical conductivity values of components but also predict dynamics of changes over time. Methods and Materials. The samples were tested under cyclic multi-axial stretching conditions. After each stretch, the strain, thickness, and electrical resistance of the samples were measured. Different materials were selected for the study, including films, nonwoven fabrics, and fabrics which differ in composition, structure, and properties. A composition with carbon nanoparticles was applied to the materials using screen printing. Results and discussion. The tests showed that the irreversible part of deformation of the sample ranged from 8% to 75%, while thickness varied from 6% to 100% depending on the structure of materials. Electrical resistance ranged from 25 Ohms to 5 KOhms, depending on test parameters and composition of coating-substrate composite. Correlation analysis confirmed strong correlation between electrical resistivity and sample deformation with correlation coefficient ranging between 0.6 and 0.78. An approximation was used to derive empirical equations that can be used to predict the reliability of flexible, electrically conductive elements under cyclic stretching conditions, which simulate operating conditions. Conclusion. A comparative analysis of test results under these conditions allowed us to recommend nonwoven fabrics and fabrics with a thickness of 0.5–0.7 mm for use as flexible electrically conducting elements. This method is recommended for objective assessment of changes in the properties of these components in intelligent building structures.