Self-cleanable, waterproof, transparent, and flexible Ag networks covered by hydrophobic polytetrafluoroethylene for multi-functional flexible thin film heaters

Abstract

We demonstrate a self-cleanable, waterproof, highly transparent, and flexible Ag network covered by a very thin transparent polytetrafluoroethylene (PTFE) layer using typical magnetron sputtering for multi-functional flexible thin film heaters used in smart windows. By passivation of the self-assembled Ag network with very thin PTFE films, we fabricated a multi-functional Ag network suitable for flexible thin film heaters. At a PTFE thickness of 10 nm, the Ag network passivated by hydrophobic PTFE layer showed a low sheet resistance of 11.64 Ohm/square, high optical transmittance of 80.20% at a wavelength of 550 nm, and high contact angle of 102.42°. In addition, sputtering of the PTFE layer on the Ag network improved the mechanical flexibility and reliability of the Ag network electrode. The flexible and transparent thin film heater (TTFH) with Ag network electrode covered by PTFE layer showed a saturation temperature of 120 °C at low voltage of 4.5 V and power of 2.45 W, as well as a hydrophobic surface suited for self-cleaning smart windows. These multi-functional performances of TTFH indicate that the Ag network/PTFE film-based flexible TTFH could be used as self-cleanable, waterproof TTFHs for curved smart windows in smart buildings and automobiles.

A Fluoropolymer-Coated Nanometer-Thick Cu Mesh Film for a Robust and Hydrophobic Transparent Heater

“…To develop more useful transparent heaters for practical applications, it is necessary to consider the droplet evaporation characteristics and wettability control on the surface of the transparent conductor-based heaters. − Kim et al demonstrated that a multifunctional transparent heater with a flexible silver nanowire network covered by a vacuum-sputtered polytetrafluoroethylene layer produced a self-cleaning, waterproof, and highly transparent surface. , In addition, Kulkarni et al reported that the surface wettability of the transparent conductor could be modified by adsorbing a monolayer of 1-hexadecanethiol on the Ag wire mesh surface . However, a few studies have been performed; thus, research on high-performance transparent heaters with controlled surface wettability is of great significance.…”

Highly flexible Ag nanowire network covered by a graphene oxide nanosheet for high-performance flexible electronics and anti-bacterial applications

“…A flexible and transparent conductive electrode (FTCE) is a thin film with high transparency, high conductivity, and outstanding flexibility [1][2][3]. Due to the rapid advancements in flexible electronics and wearable devices, FTCEs have gained a great deal of attention as a key component of flexible displays [4][5][6], flexible touch panels [7][8][9], flexible thin film heaters (TFHs) [10][11][12][13][14][15][16], photoelectric devices [17][18][19][20], and wearable electronics [21][22][23].…”

Solution-Processed Multistacked Tin-Doped Indium Oxide Nanoparticle Conductors for Cost-Effective Thin Film Heaters

“…summarized the characteristics of electrode materials used in TFH . Recently, our group has also studied various materials, such as the AgNW network, self-assembled network, W-doped In 2 O 3 , and MoO 3 –Ag–MoO 3 . − Despite the high electrical and thermal conductivities of AgNW, AgNW-based transparent conductors are easily oxidized in air, have low heat and oxidation resistance, and have a rough surface. , Furthermore, TFH electrode materials were studied through a large-area roll-to-roll process with CuO x –Cu–CuO x , InZnSiO–Ag–InZnSiO, ZnSnO–AgPdCu–ZnSnO, ITO–Cu–ITO, and ITO–Ag–ITO. − Although nanoparticle-based oxide electrode such, as InZnO, InZnSnO, InTiO, and InSnO has been reported, − research into solution-based ITO conductors and solution-multilayers for transparent TFHs is still insufficient. Specifically, studies on the crystallinity, preferred orientation, and electrical and optical properties depending on the thickness of the sputtered ITO have been conducted; − however, for the outstanding electrical and optical properties of ITO NPs, studies on optimizing the thickness and annealing process have not been sufficiently performed.…”