Piezoresistive Effect Lab Report
Since unique physical and chemical properties of graphene were discovered many works have been devoted to synthesis of graphene and graphene based composites and to investigation of their possible applications [1-5].
Graphite sheets as a filler material can lead to significant change in properties of composites. Carbon-based materials and graphite nanoparticles in particular in general enhance electronic, optical, thermal and mechanical properties of polymer matrixes [6-11]. To synthesize electroconductive composites graphite nanoparticles were used as filler material in many insulating polymers, for example epoxy, polystyrene, poly(methyl methacrylate), thermoplastic polyurethane and many others [8]. Such composites attracted significant
attention …show more content…
Piezoresistive effect is a change of electrical resistance of a conductor under axial strain. One of the main quantitative variables of piezoresistive effect is strain gauge factor (SGF). SGF is relative change of electrical resistance divided to mechanical strain (relative change of the length of the conductor). Commercial strain gauges are made with metallic and semiconducting sensing elements. SGF of metallic gauges is from 2 to 6, and for semiconducting ones it is from 40 to 200 in absolute value [15-17].
Piezoresistive effect in metallic conductors is concerned with change of geometry of them. In semiconductors the effect is concerned generally with change of specific resistance of them due to change of crystal structure , the value depending on the conduction type of material and doping dose [17]. As for SGF of conducting composites based on carbon nanomaterials, there many works reporting different value of the factor depending on the type of filler and forming method of the composites. For example composites based on graphene aerogel and polydimethylsiloxane have SGF equal to 61.3 [18]; graphene platelets in epoxy matrix showed SGF equal to
56.7 [19]; amino-functionalized graphene nanoplates …show more content…
1). The resulted dispersion was centrifuged and decanted. Film specimen was formed by flow-coating of the dispersion on a glass substrate. The film was dried at 70-80°C for 24 h.
The resulted film took off from the substrate and dried at
100°C for 24 h in vacuum and at 200°C for 2 h in air to remove the rest solvent. That way two films were obtained with 0.75 and 2.00 mass per cent of FLG in the OPBI matrix. C. Experimental samples, Methods and Apparatures
The experimental samples were formed by cutting the films synthesized to strips 2 mm in width and 8 mm in length. To deform the experimental samples beams of uniform strength (in bending) were used as in [31]. The beams were covered with polymer glue for dielectric insulation. The strips were bonded onto the beams with cyanoacrylate adhesive using standard technique as for metallic strain gauges. The electrical contacts to the samples were made of silver paste and thin copper leading wires were used. To measure resistances of the samples four-point and two-point probe methods were used.
The beams with samples were loaded with
Graphite sheets as a filler material can lead to significant change in properties of composites. Carbon-based materials and graphite nanoparticles in particular in general enhance electronic, optical, thermal and mechanical properties of polymer matrixes [6-11]. To synthesize electroconductive composites graphite nanoparticles were used as filler material in many insulating polymers, for example epoxy, polystyrene, poly(methyl methacrylate), thermoplastic polyurethane and many others [8]. Such composites attracted significant
attention …show more content…
Piezoresistive effect is a change of electrical resistance of a conductor under axial strain. One of the main quantitative variables of piezoresistive effect is strain gauge factor (SGF). SGF is relative change of electrical resistance divided to mechanical strain (relative change of the length of the conductor). Commercial strain gauges are made with metallic and semiconducting sensing elements. SGF of metallic gauges is from 2 to 6, and for semiconducting ones it is from 40 to 200 in absolute value [15-17].
Piezoresistive effect in metallic conductors is concerned with change of geometry of them. In semiconductors the effect is concerned generally with change of specific resistance of them due to change of crystal structure , the value depending on the conduction type of material and doping dose [17]. As for SGF of conducting composites based on carbon nanomaterials, there many works reporting different value of the factor depending on the type of filler and forming method of the composites. For example composites based on graphene aerogel and polydimethylsiloxane have SGF equal to 61.3 [18]; graphene platelets in epoxy matrix showed SGF equal to
56.7 [19]; amino-functionalized graphene nanoplates …show more content…
1). The resulted dispersion was centrifuged and decanted. Film specimen was formed by flow-coating of the dispersion on a glass substrate. The film was dried at 70-80°C for 24 h.
The resulted film took off from the substrate and dried at
100°C for 24 h in vacuum and at 200°C for 2 h in air to remove the rest solvent. That way two films were obtained with 0.75 and 2.00 mass per cent of FLG in the OPBI matrix. C. Experimental samples, Methods and Apparatures
The experimental samples were formed by cutting the films synthesized to strips 2 mm in width and 8 mm in length. To deform the experimental samples beams of uniform strength (in bending) were used as in [31]. The beams were covered with polymer glue for dielectric insulation. The strips were bonded onto the beams with cyanoacrylate adhesive using standard technique as for metallic strain gauges. The electrical contacts to the samples were made of silver paste and thin copper leading wires were used. To measure resistances of the samples four-point and two-point probe methods were used.
The beams with samples were loaded with