Dual–Plasticizing Strategy for an Enhanced Performance of Degradable Chitosan-Based Triboelectric Nanogenerators

Chitosan (CS), as the polymer friction layer of triboelectric nanogenerators (TENGs), has great potential for application in the development of degradable wearable sensors. However, its mechanical properties and output performance require further improvement. Although introducing plasticizers into polymers can simultaneously increase their mechanical properties and TENG output, this strategy remains unexplored for degradable polymer TENGs, which exhibit great potential as green materials in electromechanical conversion. Herein, we used glycerol and polyethylene glycol as plasticizers to enhance tensile properties and output properties of the CS TENG. Plasticizer incorporation resulted in an improved surface roughness and the introduction of numerous −OH groups, thereby improving the tribo-positive electrical generation of CS. The maximum open–circuit voltage can reach 173 V, which was three times higher than that of pure CS-based TENGs. Moreover, reduced Young’s modulus of this film made it more advantageous for flexible sensor applications, and throat sensing and handwriting recognition were realized. Finally, the CS sensor exhibited antibacterial activity and complete degradability in soil within 36 days. Overall, this plasticizing method is expected to be extensively studied in the field of degradable, wearable polymer TENG sensors

Dual–Plasticizing Strategy for an Enhanced Performance of Degradable Chitosan-Based Triboelectric Nanogenerators

Chitosan (CS), as the polymer friction layer of triboelectric nanogenerators (TENGs), has great potential for application in the development of degradable wearable sensors. However, its mechanical properties and output performance require further improvement. Although introducing plasticizers into polymers can simultaneously increase their mechanical properties and TENG output, this strategy remains unexplored for degradable polymer TENGs, which exhibit great potential as green materials in electromechanical conversion. Herein, we used glycerol and polyethylene glycol as plasticizers to enhance tensile properties and output properties of the CS TENG. Plasticizer incorporation resulted in an improved surface roughness and the introduction of numerous −OH groups, thereby improving the tribo-positive electrical generation of CS. The maximum open–circuit voltage can reach 173 V, which was three times higher than that of pure CS-based TENGs. Moreover, reduced Young’s modulus of this film made it more advantageous for flexible sensor applications, and throat sensing and handwriting recognition were realized. Finally, the CS sensor exhibited antibacterial activity and complete degradability in soil within 36 days. Overall, this plasticizing method is expected to be extensively studied in the field of degradable, wearable polymer TENG sensors

Novel Method for the Fabrication of Flexible Film with Oriented Arrays of Graphene in Poly(vinylidene fluoride-<i>co</i>-hexafluoropropylene) with Low Dielectric Loss

Carbon–polymer nanocomposites with good dielectric properties have potential applications in the electronic and electrical industry because of their good mechanical properties and low cost. The morphology, structure, dielectric properties, and mechanical strength of reduced-graphene oxide nanosheet/poly­(vinylidene fluoride-<i>co</i>-hexafluoropropylene) nanocomposites (rGO/PVDF-HFP) were investigated. The rGO nanosheets were well dispersed and strongly oriented in the matrix, thanks to the unique spin-assistant preparation process. A dielectric constant of 54 (100 Hz) which was four times higher than that of pure PVDF-HFP was obtained when the concentration of rGO was 0.7 vol % and the dielectric loss was as low as 0.27. The good dielectric performance of the nanocomposites was attributed to the homogeneous dispersion and good alignment of rGO. The shear force provided by spin-coating, the thickness decreasing process, and thickness control were assumed to be key factors in the alignment of rGO nanosheets in the nanocomposite films. At the same time, the aligned rGO sheets increased the percolation threshold of the composite which shed light on the mechanism for obtaining low loss materials