Hybrid Conductive Films Research Articles

Stretchable, ultrasensitive strain sensor with high-linearity by constructing crack-based dual conductive network

An increasing attention has been paid to crack-based strain sensors due to their ultrahigh sensitivity. However, two main challenges with such sensors still need to be addressed. Firstly, most crack-based sensors face a trade-off between sensitivity and detection range. Secondly, the problem of low linearity occurs widely among crack-based sensors. This paper presents a simple and efficient method to obtain a multidimensional (1D/2D) crack-based stretchable sensor with dual conductive (electronic/ ionic) network. The process involves creating a hybrid conductive film consisting of Ti3C2Tx MXene nanosheets (MXene) and carbon nanotubes (CNTs) via vacuum-assisted filtration, and developing a flexible substrate with ionic conductivity through convenient UV-initiated curing. The prepared sensor exhibited a broad range of workable strain (0–389 %), high sensitivity (GF = 216.8), rapid response/ recovery (165 ms/ 86 ms) and exceptional durability. Most notably, this strain sensor demonstrates strong linearity (R2 = 0.983) with the synergistic effect of the dual conductive network and cracked hybrid film, an advantage over other crack-based sensors. Therefore, our novel dual-conductive strain sensors, with its superior comprehensive performance, can effectively monitor various large and subtle human movements, including joint bending, pulse, and speech recognition. It is credible that this highly stretchable sensor possesses tremendous potential in human motion monitoring, personal healthcare monitoring, and human–computer interaction.

Non-metallic copolymer material-based universal bio-abiotic hybrid platform for boosting the efficient electronic collection of microbial fuel cells

Synthetic cationic-pyrrole copolymer for forming an abio–abiotic hybrid conductive film with microbe cells on graphite felt of the electrode of an MFC, leading to high efficiency performance for electrogenesis.

Sequential manufacturing via intra-additive hybrid materials approach for fully roll-to-roll processed flexible organic thin film transistors

Conventional conductive films that are used as electrodes in organic thin film transistors (OTFTs) are susceptible to mechanical deformation, limiting the applicability of such films in flexible wearable electronic devices. To address this limitation, a hybrid conductive film (HCF) consisting of silver nanowires (NWs) and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) fabricated through roll-to-roll (R2R) slot-die coating is presented for use as a gate electrode in OTFTs. Mechanical stability compares by bending and taping test measurement quantitatively. Coating flow rate significantly influences sheet resistance and transmittance. A performance evaluation of the OTFTs with the Ag NW/PEDOT:PSS HCF as the gate electrode shows that the charge carrier mobility and on/off current ratio are 2.168 cm2 V−1 s−1 and 6 × 105, respectively. In addition, the HCF is highly flexible, and the HCF-based OTFTs exhibit 57% less mobility reduction than a conventional OTFT based on silver ink after 50,000 bending cycles with a 2 mm bending radius. These results highlight the potential of the fabricated HCF as an electrode material for flexible electronic devices.

Elucidation of the Controversial Layer Growth Mechanism of Vapor Phase Polymerization in the Preparation of Conductive Poly(3,4‐ethylenedioxythiophene)‐SiO2 Hybrid Films

AbstractIn recent times, there have been debates to ascertain whether the growth mechanism in vapor phase polymerization is a top‐down or a bottom‐up process. The objective of the present study is to identify the formation mechanisms of the organic–inorganic hybrid film prepared in the gaseous phase on the basis of the practical importance of the hybridization of materials. To this end, poly(3,4‐ethylenedioxythiophene)‐SiO2 conductive hybrid films with different layered structures are successfully fabricated. The growth mechanism of the layered organic–inorganic conductive hybrid thin film is elucidated by investigating the variations in the morphological and chemical compositions of its surface. Additionally, a cross‐sectional analysis is performed using a scanning electron microscope‐energy dispersive X‐ray spectroscopy and X‐ray photoelectron spectroscopy. The results indicate a “bottom‐up” growth mechanism, wherein the oxidant diffused through the recently formed layer, generating novel layers; this ultimately leads to formation of the organic–inorganic conductive hybrid film. Moreover, the optoelectronic and mechanical properties of the hybrid conductive films are precisely controlled by adjusting the order of incorporation of monomers in the process and the duration of polymerization of each monomer. Thus, this study achieves the fabrication of a mechanically robust and optically enhanced conductive hybrid film.

Human-Finger Electronics Based on Opposing Humidity-Resistance Responses in Carbon Nanofilms.

Carbon nanomaterials have excellent humidity sensing properties. Here, it is demonstrated that multiwalled carbon-nanotube (MWCNT)- and reduced-graphene-oxide (rGO)-based conductive films have opposite humidity/electrical resistance responses: MWCNTs increase their electrical resistance (positive response) and rGOs decrease their electrical resistance (negative response). The authors propose a new phenomenology that describes a "net"-like model for MWCNT films and a "scale"-like model for rGO films to explain these behaviors based on contributions from junction resistances (at interparticle junctions) and intrinsic resistances (of the particles). This phenomenology is accordingly validated via a series of experiments, which complement more classical models based on proton conductivity. To explore the practical applications of the converse humidity/resistance responses, a humidity-insensitive MWCNT/rGO hybrid conductive films is developed, which has the potential to greatly improve the stability of carbon-based electrical device to humidity. The authors further investigate the application of such films to human-finger electronics by fabricating transparent flexible devices consisting of a polyethylene terephthalate substrate equipped with an MWCNT/rGO pattern for gesture recognition, and MWCNT/rGO/MWCNT or rGO/MWCNT/rGO patterns for 3D noncontact sensing, which will be complementary to existing 3D touch technology.

Large-scalable RTCVD Graphene/PEDOT:PSS hybrid conductive film for application in transparent and flexible thermoelectric nanogenerators

Poly(3,4-ethyldioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), as a thermoelectric(TE) material, exhibits a high electrical conductivity and ZT value (10−1–100).

Influence of base inhibitor and surfactant on the electrical and physicochemical properties of PEDOT-SiO2 hybrid conductive films

This paper describes the synthesis of poly(3,4-ethylenedioxythiophene)-SiO2 hybrid conductive films possessing superior mechanical properties and improved opto-electrical properties. A mixture of a 3,4-ethylenedioxythiophene (EDOT) monomer and an optimized amount of a tetraethyl orthosilicate (TEOS) SiO2 precursor was co-vaporized and synchronously polymerized on a ferric p-toluenesulfonate (FTS)-coated poly-(ethylene terephthalate) (PET) substrate. The opto-electrical properties of the mechanically robust PEDOT-SiO2 hybrid films were improved by adding a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG) triblock copolymer surfactant and an imidazole base inhibitor to the FTS oxidant solution. These two additives served to control polymerization and prohibit crystallization, resulting in conductive thin films with smooth and homogeneous morphologies. Additionally, the additives improved the physicochemical properties of the films, as determined by their pencil hardness, solvent resistance, and scratch resistance. Finally, these additives yielded hybrid thin films that showed good electrical and optical stability over time. Open image in new window

수분산 Polyurethane/Poly(3,4-ethylenedioxythiophene) 혼성 필름의 물리화학적 특성 향상

Poly(3,4-ethylenedioxythiophene) (PEDOT) has good properties such as high conductivity, optical transmittance, and chemical stability, while offering relatively weak physicochemical properties. The main purpose of this paper is the improvement of physicochemical properties such as solvent resistance and pencil hardness of PEDOT. Carboxyl groups in the anionic type waterborne polyurethane (WPU) chains can effectively crosslink each other in the presence of aziridine, resulting in physicochemically robust PEDOT/WPU organic-organic hybrid conductive thin films. The electrical conductivity, optical properties, and physicochemical properties of the hybrid conductive film were compared by varying the solid content and WPU portion in the coating precursor solution. From the results, the transparency and surface resistance of the hybrid film show a decreasing tendency with increasing solid content in the coating precursor. Moreover, solvent resistance and hardness were dramatically enhanced by hybridization of PEDOT and crosslinked WPU due to curing reactions between carboxyl groups.

Study on the Electrical, Optical, and Physicochemical Properties of Poly(MMA-co-MAA)/Poly(3,4-ethylenedioxythiophene) Hybrid Thin Films

Poly(3,4-ethylenedioxythiophene) (PEDOT) has good properties as a conductive polymer such as high conductivity, optical transmittance, and chemical stability, while offering relatively weak physicochemical properties. The main purpose of this paper is to improve physicochemical properties such as solvent resistance and pencil hardness of PEDOT. Carboxyl groups in the poly(MMA-co-MAA) polymer chains can effectively crosslink each other in the presence of aziridine, resulting in physicochemically robust PEDOT/poly(MMA-co-MAA) hybrid conductive films. The electrical conductivity, optical properties, and physicochemical properties of the hybrid conductive film were compared by varying the solid content and poly(MMA-co-MAA) portion in the coating precursor solution. From the results, the transparency and surface resistance of the hybrid film show a tendency to decrease with increasing solid content in the coating precursor. Moreover, solvent resistance and hardness were dramatically enhanced by hybridization of PEDOT and crosslinked poly(MMA-co-MAA) due to curing reactions between carboxyl groups. The chemical composition of 30 wt-% of poly(MMA-co-MAA) (MMA:MAA mole ratio 9:1) and 3 wt-% - 5 wt-% of aziridine yields the best physicochemical properties of poly(MMA-co-MAA)/PEDOT hybrid thin films.

Mechanically robust poly(3,4-ethylenedioxythiophene)–SiO2 hybrid conductive film prepared by simultaneous vapor phase polymerization

Abstract This paper presents a poly(3,4-ethylenedioxythiophene)–SiO 2 hybrid conductive film with enhanced physicochemical properties such as surface hardness, solvent mechanical wear resistance, and resistance to scratch prepared via co-vaporization and simultaneous polymerization of 3,4-ethylenedioxythiophene (EDOT) and tetraethyl orthosilicate (TEOS) on a ferric p -toluenesulfonate (FTS) coated substrate. Moreover, the conductivity of the fabricated PEDOT–SiO 2 hybrid films is much higher than that of a pristine PEDOT film due to a surface smoothness effect endowed by the SiO 2 component in the hybrid film. Si content in the hybrid film obviously increased with FTS concentration, which can act as a catalyst for hydrolysis/condensation of TEOS. The demonstrated methodology for preparing poly(3,4-ethylenedioxythiophene)–SiO 2 hybrid composite films by co-vaporization/simultaneous polymerization has strong potential for the preparation of highly mechanically robust conductive thin films.

Sol-gel-derived hybrid conductive films for electromagnetic interference (EMI) shielding

The conductive nano-sized zinc particles were embedded in an insulating amorphous silica matrix, and the hybrid films were obtained by a sol-gel method. The stable hybrid sol solution was prepared by hydrolysis and condensation of Methyltrimethoxysilane (MTMS) with a one-step acidic catalyst process. Hybrid films were dip-coated on silicon wafer and cured at 120 °C for 60 minutes. The structural characterization of hybrid films were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy and X-ray diffraction (XRD). The electrical properties of the films were examined with four-point probe. Hybrid films showed to be relatively dense, uniform and defect free. The conductivity of hybrid films was varied with the different contents of zinc nanoparticles and the thickness of the film. It was observed that there was the percolation threshold for the film’s electrical properties.