Performance Comparison of Fast, Transparent, and Biotic Heaters Based on Leaf Skeletons

Abstract

Bioinspired, highly flexible, fast, and biodegradable heaters are fabricated based on Ag nanowires and leaf skeletons of different plant species. The leaf skeletons act as transparent substrates with a high surface‐area‐to‐volume ratio and allow a uniform dispersion of the Ag nanowires through the surface. Ag nanowires adhered to the leaf skeletons display very good transmittance (up to ≈87%) and mechanical (flexibility) properties (curvature values >800 m−1) without any post‐treatment. The flexible leaf skeleton‐based heaters reach high temperatures very quickly, with very low voltages (<4 V). The performance of the bioinspired heater surface is dependent on the types of fractal structures at the microscale. The morphology of the leaf skeletons is studied in detail and is corelated with the transmittance, flexibility, and sheet resistances. Bioinspired heater surfaces based on different leaf skeletons are compared based on their multiscale morphology, and the different heating performance parameters are screened. Based on the study conducted, insights on the best‐performing biotic design for the fabrication of the heaters that are useful in practical wearable, medical, or industrial heating applications are provided.

Biodegradable, Flexible Transparent Ordered Ag NWs Micromesh Conductor for Electrical Heater and Electromagnetic Interference Shielding Applications

“…As shown in Figure 2, Ag NWs micromeshes with varying ring sizes (∼8−40 μm) can be achieved to tune the optical−electrical property, which were relatively homogeneous and controllable. There are also some other approaches to prepare metal nanowire bundled network electrodes with the assistance of templates such as ice, 51 leaf skeletons, 52 and random crack molds, 53 where the templates are required and the fabrication processes are complicated. As a comparison, the Ag NMs electrode preparation with the spray-assisted self-assembly method does not require a template.…”

Fractal-like Hierarchical CuO Nano/Microstructures for Large-Surface-to-Volume-Ratio Dip Catalysts

“…Generally, there is a significant variation in the size, vein orientation, area coverage, fractal dimensions, and topographies between the leaf skeletons of different plant species. , In this work, leaves of B. racemosa were chosen due to their commercial availability, high surface area, and interesting fractal structures. Figure displays the SEM images of the leaf skeletons before the electrodeposition, after Cu deposition, and after oxidation.…”

Breathable, Flexible, Transparent, Hydrophobic, and Biotic Sustainable Electrodes for Heating and Biopotential Signal Measurement Applications

“…[ 24 ] Figure S1, Supporting Information, shows the structure of the vascular bundles along with the interconnected fibers of the H. brasiliensis where the fiber interconnection gap is calculated to be in the range of ≈50–200 μm and short cell blocks in the range of ≈5–15 μm that are known to provide better flexibility to the skeletal structures as reported elsewhere. [ 16 ] Figure S2, Supporting Information, shows the SEM image of Ag nanowire‐coated skeleton surfaces without Au coating. From the SEM image, it can be seen that the Ag nanowires are present on the skeleton surface, but not attached very conformally as compared to HBCN where the Au layer is present beneath (refer Figure 1b).…”

“…In our previous work, we developed a biocompatible, flexible, and transparent electrode for heaters by using a fractal‐like leaf skeleton and silver nanowires where we used a drop‐cast method for the deposition of nanowires on the leaf skeletons. [ 16 ] The fractal‐like structure of the leaf skeleton tends to increase the surface area to volume ratio which improves the electrical conductivity of the electrode even during the bending. Herein, we propose an improved design of the leaf‐skeleton‐based electrode which is more electrically stable and shows hydrophobic behavior.…”

“…[15] In the field of flexible electronics, one can take advantage of fractal-like designs as they present a higher surface area-to-volume ratio compared with conventional flat surfaces. [16] Likewise, fractal designs can provide an efficient collection and transfer of electrical and thermal energy, and they have been applied in different applications such as photovoltaic, sensors, antennas, etc. [17][18][19] Fractal-like patterns consist of a series of self-repeating patterns on different scales.…”