Glass fiber/epoxy composites with integrated layer of carbon nanotubes for deformation detection

An entangled multiwalled carbon nanotube film (Buckypaper) embedded in a polyurethane membrane was integrated into a glass fiber reinforced epoxy composite by means of a vacuum infusion to become a part of the composite and to give it a strain self-sensing functionality. In order to increase the strain sensing, pristine nanotubes were either oxidized by KMnO4 or Ag particles were attached to their surfaces. Moreover, the design of the carbon nanotube/polyurethane sensor allowed a formation of a film of micro-sized cracks, which increased its reversible electrical resistance and resulted in an enhancement of the strain sensing. Prestaining of the sensor with Ag-decorated nanotubes increased its sensitivity to strain, which was quantified by a gauge factor, more than hundredfold in comparison with the sensor with pristine nanotubes. The tests revealed that the integrated strain sensing exhibited a long-term electromechanical stability, which was linked to the level of strain in the host glass fiber/epoxy composite. © 2017 Elsevier LtdBMWFW, Bundesministerium für Wissenschaft, Forschung und Wirtschaft; OEAD, OeAD-GmbHMinistry of Education, Youth and Sports of the Czech Republic, under the project Czech-Austrian mobility (program KONTAKT II) [7AMB16AT033]; OEAD, the Austrian Agency for International Mobility and Cooperation in Education; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [101504]; Operational Program Research and Development for Innovations - European Regional Development Fund (ERDF); national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409]; TBU in Zlin [IGA/CPS/2017/002]; Austrian Federal Ministry of Science, Research and Economy; FACC Operations GmbH as industrial partner of the Christian Doppler Laboratory for High Efficient Composite Processing; Fund of the Institute of Hydrodynamics [AV0Z20600510