RESUMO
In this work, a textile-based triboelectric nanogenerator (TENG) device was developed through electroless plating technology to prepare electrode material. Hydrophilic groups on the fiber surface are able to absorb Ag+, which could play a role in the center of a catalyst to reduce Cu2+ to fabricate Cu-coated cotton toward the fabrication of TENG electrode material. The TENG device established admirable performance and good stabilization, and a maximum voltage at 9.6 V was detected when the stress and strain on the polydimethylsiloxane layer are 82.6 kPa and 5.8%, respectively. In addition, the relationships among device properties and strain/thickness of dielectric materials have been explored in depth as well. The output voltage of the device increases gradually with the enhancement of dielectric strain and stress. As expected, the TENG as-fabricated device was installed to various physical behaviors to illustrate the harvesting of power of knee-jerk movements.
RESUMO
Textile-based triboelectric nanogenerator (T-TENG) devices, particularly, narrow-gap mode, have been conceived and developed for obtaining energy harvesting and tactile sensing devices unaffected by the external environment. Enhancing the interfacial area of T-TENG materials offers exciting opportunities to improve the device output performance. In this work, a narrow-gap T-TENG was fabricated with a facile process, and a new strategy for improving the device output is proposed. The new structural sensor (polydimethylsiloxane (PDMS)-encapsulated electroless copper plating (EP-Cu) cotton) with multiple electricity generation mechanism was designed and fabricated for enhancing recognition accuracy. The result shows that only PDMS layer strain was established at an external stress of 1.24-12.4 kPa and the fibers laterally slip at a stress of 12.4-139 kPa; more importantly, the output performance of the TENG displayed a linear relationship under corresponding stress ranges. The as-fabricated device demonstrated the ability to convert different energies such as vibration, raindrops, wind and human motions into electrical energy with excellent sensitivity. Interestingly, the output signal of the as-fabricated TENG device is a combination of output signals from PDMS/EP-Cu and PDMS/recognition object devices. To be precise, there are two TENG devices (PDMS/EP-Cu and PDMS/recognition object) that work when the as-fabricated TENG device is under 12.4-139 kPa stress. Accompanied by unique characteristics, the generated TENG signals are capable of recognition of contact materials. Combining the TENG signal and deep learning technology, we explore a strategy that can enable the as-fabricated device to recognize 8 different materials with 99.48% recognition accuracy in the natural environment.
RESUMO
The exploration of flexible resistive sensors with excellent performance remains a challenge. In this paper, a nickel-coated carbon tube with a textured structure was prepared as a conductive sensitive material and inserted into the poly(dimethylsiloxane) (PDMS) polymer; interestingly, the sensor performance was controlled by the elastic modulus of the matrix resin. The results show that Pd2+ may be adsorbed by the active groups on the surface of a plant fiber as a catalytic center for the reduction of Ni2+. After 300 °C annealing, the inner plant fiber would be carbonized and attached to the outside of the nickel tube; to be precise, the textured Ni-encapsulated C tube was fabricated successfully. It is worth noting that the C tube serves as a layer of support for the external Ni coating, providing sufficient mechanical strength. In addition, resistance sensors with different properties were prepared by controlling the elasticity modulus of the PDMS polymer by introducing different contents of curing agents. The limit uniaxial tensile strain was enhanced from 42 to 49% and sensitivity reduced from 0.2 to 2.0% with the elasticity modulus of the matrix resin increasing from 0.32 to 2.2 MPa. As expected, the sensor is obviously appropriate for the detection of elbow joints, human speaking, and human joints with the reduction of the elasticity modulus of the matrix resin. To be precise, the optimal elastic modulus of the sensor matrix resin would facilitate the improvement of its sensitivity to monitor different human behaviors.
RESUMO
The exploration of flexible and lightweight electromagnetic interference (EMI) shielding materials with excellent shielding effectiveness, as a means to effectively alleviate electromagnetic pollution, is still a tremendous challenge. This paper proposes a conducting material named the textured Ni-encapsulated carbon tube, which can be applied in EMI shielding material by being inserted in the center of a poly(dimethysiloxane) (PDMS) polymer. We demonstrated that Pd2+ could be absorbed by the active groups on the plant fiber surface to catalyze the reduction of Ni2+ as a catalytic center by means of a textured Ni-encapsulated plant fiber. Owing to the outstanding heat-conducting capability of the Ni coating, the inner plant fiber was carbonized and attached to the Ni-tube inside the surface during annealing. To be precise, the textured Ni-encapsulated C tube was fabricated successfully after annealing at 300 °C. On further increasing the annealing temperature, the C tube disappeared gradually with the Ni coating being oxidized to NiO. Of note, the C tube acted as a support layer for the external Ni coating, providing sufficient mechanical strength. When combined with the coating PDMS layer, a flexible and lightweight EMI shielding material is fabricated successfully. It displays an outstanding EMI shielding effectiveness of 31.34 dB and a higher specific shielding efficiency of 27.5 dB·cm3/g, especially showing excellent mechanical property and flexibility with only 2 mm thickness. This study provides a new method to fabricate outstanding EMI shielding materials.
RESUMO
The inefficiency of conventional photocatalytic treatment for removing rhodamine B is posing potential risks to ecological environments. Here, we construct a highly efficient photocatalyst consisting of Ag3PO4 and α-Fe2O3 hybrid powders for the treatment of rhodamine B. Ag3PO4 nanoparticles (nanoparticles, about 50 nm) are uniformly dispersed on the surface of α-Fe2O3 microcrystals (hexagonal sheet, about 1.5 µm). The Ag3PO4-deposited uniformity on the α-Fe2O3 surface first increased, then decreased on increasing the hybrid ratio of Ag3PO4 to α-Fe2O3. When the hybrid ratio of Ag3PO4 to α-Fe2O3 is 1 : 2, the distribution of Ag3PO4 particles on the sheet α-Fe2O3 is more uniform with excellent Ag3PO4/α-Fe2O3 interface performance. The catalytic degradation efficiency of hybrids with the introduction of Ag3PO4 nanoparticles on the α-Fe2O3 surface reached 95%. More importantly, the hybrid material exhibits superior photocatalytic stability. Ag3PO4/α-Fe2O3 hybrids have good reusability, and the photocatalytic efficiency could still reach 72% after four reuses. The excellent photocatalytic activity of the as-prepared hybrids can be attributed to the heterostructure between Ag3PO4 and α-Fe2O3, which can effectively inhibit the photoelectron-hole recombination and broaden the visible light response range.
RESUMO
Excellent stability of a catalytic center would facilitate the prolongation of the cycle of a chemical plating bath and the reduction of environmental pollution. In this study, silane (3-aminopropyltriethoxysilane (KH550) and γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560)) was incorporated in AgNO3 solution to rationally prepare a Ag nanoparticle/polymer brush (Ag/PB) catalytic solution. The effects of the KH560 relative content on the Ag/PB structure and stability were studied. The epoxy group in the KH560 could react with an amino group in the KH550 through direct ring-opening reaction to form a secondary amino group and hydroxyl, which could coadsorb Ag nanoparticles by means of a chelating structure; hence, Ag/PB with superior Ag-adsorbed intensity was established on a polyethylene terephthalate (PET) surface. Ag particles on PB with 75% KH560 revealed the best stability of those measured, and the relative Ag surplus was 56.7% after stability testing. The generated Ag/PB that served as catalytic centers to catalyze the electroless copper plating resulted in a facile technology for preparing Cu/PET composite material. This means that the technology has potential application in a green process for preparing metal/polymer composite materials.
RESUMO
In this work, Ni particles/PA12 powders (Ni/PA12) and graphite oxide (GO)-encapsulated Ni particles/PA12 powders (GO-Ni/PA12) composite powders were prepared by defect-included electroless plating technique, and its laser sintered behaviour was investigated. Results showed that a lot of defects could formed on the surface of CH3COOH etched PA12 powders. The defects would induce Ni and GO-Ni particles independently plated on the PA12 surface. Adding GO in the plating solution would facilitate the deposition of Ni particles, GO, and NiO on the PA 12 surface, but inhibit the growth and the crystallinity of the Ni particles. The SLS process involved the contact of PA12 powders, the formation of sintering neck, the growth of sintering neck and the formation of fused solid. Sintering process could facilitate the re-arrangement of Ni particles due to surface tension and the growth of sintering neck. The Ni particles had well wettability, and the interfaces between Ni particles and PA 12 were contacted soundly. The tensile strength and bending strength of the 10 W-sintered Ni/PA12 specimen were 50 MPa and 60 MPa. But SLS process caused the serious aggregation of GO-Ni particles due to higher concentration, activity and surface area of GO-Ni particles.
