Electrical and Thermal and Self-Healing Properties of Graphene-Thermopolyurethane Flexible Conductive Films

Abstract

We fabricated graphene-thermopolyurethane (G-TPU) flexible conductive film by a blending method and systematically investigated the electrical, thermal and self-healing properties of the G-TPU flexible conductive film by infrared light and electricity. The experimental results demonstrate that the G-TPU composite films have good conductivity and thermal conductivity in the appropriate mass content of graphene in the composite film. The composite films have the good electro-thermal and infrared light thermal response performances and electro-thermal response performance is closely related to the mass content of graphene in the composite film, but the infrared light thermal response performance is not. The scratch on the composite film can be completely healed, using electricity or infrared light. The healing efficiency of the composite film healed using infrared light is higher than that of using the electricity, while the healing time of the composite film is shorter. Regardless of the self-healing method, the temperature of the self-healing is a very important factor. The self-healing conductive composite film still exhibits a good conductivity.Nanomaterials 2020, 10, 753 2 of 16 of the material can be automatically healed to improve the safety, lifetime, and environmental impact of man-made materials [16][17][18][19][20][21]. To obtain self-healing materials, many strategies have been explored, such as micro-containers containing healing agent and microvascular networks in the matrix, dynamic chemical bonds or weak interaction [22][23][24][25][26][27]. These self-healing materials can realize self-healing by using a large number of healing agents [28,29]. In theory, they can realize multiple self-healing of the damaged materials with the assistance of external light, heat, and electric field, et al. Although, great progress has been made in the research of the self-healing materials and techniques, there are still some critical problems that restrict their applications, such as low mechanical properties after healing, high cost, time-consuming, and low efficiency. Therefore, it is significant to fabricate a self-healing polymer and composites based on new materials, and then explore their potential applications, as well as new healing method.Graphene (G), a novel two-dimensional material, possesses large specific surface area, superior mechanical property, as well as being an excellent conductor of both heat and electricity, and having a good microwave and infrared absorbing capacity, so they have strong response to electricity and electromagnetic waves and infrared radiation (IR) [30][31][32][33][34]. Graphene is often used as fillers in preparing functional composites. Based on these properties, researchers fabricated graphene-based self-healing polymer composites by introducing graphene into the polymer [34,35]. Kim et al. reported, for the first time, self-healable PU nanocomposites, containing modified graphene by the near IR absorption of graphene [36]. Huang et al. prepared TPU containing few layers of g...

Influence of Characteristics of Thermoplastic Polyurethane on Graphene-Thermoplastic Polyurethane Composite Film

“…Chen et al reported that they prepared stretchable and conductive G-TPU nanocomposite foam materials via water vapor induced phase separation technology [ 18 ]. Strankowski et al reported that they used graphene nanoplates and reduced graphene oxide as fillers to prepare two kind of thermally reinforced and mechanically reinforced TPU composites [ 25 ]. Cataldi et al reported that they prepared self-healing flexible conductive cotton textiles by impregnating cotton fabrics in graphene and thermoplastic polyurethane-based dispersions [ 26 ].…”

High Performance of Thermoplastic Polyurethane-Graphene Oxide Self-Healing Composite Film

“…The photothermal conversion temperature in this area is higher than the surroundings, so, "hot spots" are formed [39,41]. It should be pointed out that the near-infrared photothermal conversion efficiency of the GO-TPU film is slightly different from that of the graphene-TPU film we previously reported [44]. Comparing the experimental results of the two, it can be seen that the near-infrared photothermal conversion efficiency of graphene is higher than that of GO.…”

“…In addition, with the increase of the infrared lamp irradiation time, the sample surface gradually brightened. This may be due to the thermal melting and solidification of the GO-TPU film [16,[42][43][44][45]. After the infrared lamp is turned on, as the irradiation time increases, the scratch is gradually repaired.…”

“…In addition, with the increase of the infrared lamp irradiation time, the sample surface gradually brightened. This may be due to the thermal melting and solidification of the GO-TPU film [42][43][44][45][46]. Figure 13 displays the SEM images of GO-TPU film with TPU initial concentration of 20 wt % and different loadings of GO under the irradiation of an infrared lamp with an infrared light intensity of 3450 lux for 10 min.…”

“…The good photothermal conversion efficiency of GO makes the temperature of GO-TPU film rise rapidly in a short time. When the rising temperature is higher than the glass transition temperature (Tg) of the GO-TPU film, the soft chains of TPU can move freely, causing wetting, diffusion, and surface rearrangement between the polyurethane molecular chains, so that the GO-TPU composite film can be repaired [16,44,45]. In order to study the effect of the initial concentration of TPU on the self-healing performance of GO-TPU film, we tested the self-healing performance of the scratch GO-TPU films with 2 wt % and the initial concentration of TPU of 10 wt %, 20 wt %, and 30 wt %, respectively, by using optical image.…”