University of Electronic Science and Technology of China

Xiaosong Du

Yadong Jiang

Huiling Tai

Guangzhong Xie

Weizhi Li

Yi Bu Li

Zhen Yuan

Jimeng Li

Ze Wu

Dong Qiu

Qichen Gong

Yuanjie Su

Penglin Wu

Huan Yuan

Yuming Wu

Dongsheng Wang

Luhua Cheng

Yujin Yao

Mingliang Yao

He Yu

Jinyang Yi

Chunxu Chen

Xueliang Ye

Li Jia

Rui Guo

Yanmeng Chen

Xulan Zhao

The disclosure relates to a wireless self-powered gas sensor based on electromagnetic oscillations triggered by external forces and its fabrication method. The sensor includes a gas test chamber, a first friction layer, a second friction layer, an interdigital electrode, a gas-sensitive material, an air inlet, an air outlet and leads. The gas sensor of the disclosure is an integrated detection system of 'environmental energy collection&#x2014;wireless energy transmission&#x2014;active spontaneous detection' that can be driven simultaneously only by external mechanical movement, and can work independently without external power supply. The first friction layer and the second friction layer are arranged outside the gas test chamber. The frictional motion will not interfere with the flow field of the test chamber and the gas molecule absorption and desorption, which ensures the stability of gas detection to the greatest extent.

Wireless self-powered gas sensor based on electromagnetic oscillations triggered by external forces and fabrication method thereof

A self-powered automobile exhaust gas sensor including a supporting frame, a ferroelectric-triboelectric coupling functional film, and two metal electrodes. The ferroelectric-triboelectric coupling functional film comprises a first end fixed on the supporting beam in middle of the supporting frame, and a second end is freestanding. The two metal electrodes are grounded and adhered on the upper and lower sides of the supporting frame, respectively. An iron block is mounted on the top of the supporting frame. The ferroelectric-triboelectric coupling functional film includes a negative triboelectric charging layer, a ferroelectric composite material layer and a positive triboelectric charging layer; the ferroelectric composite material layer is prepared via casting method by mixing the ferroelectric material and the gas-sensitive material; the negative triboelectric charging layer has stronger electron affinity ability than the positive triboelectric charging layer, and attracts electrons from the positive triboelectric charging layer.

Self-powered automobile exhaust gas sensor and preparation method thereof

A one-step solution casting method for preparing a PVDF-based pyroelectric polymer film is provided, which belongs to the technical field of functional material preparation. The method comprises steps of: treating a substrate with a hydrophilic reagent to obtain a hydrophilically-modified substrate, and then casting the organic solution of polyvinylidene fluoride (PVDF) or its copolymer on the hydrophilically-modified substrate. After cured, the as-casted PVDF-based film shows pyroelectricity without undergoing any stretching or poling post-treatment, indicates that the dipoles of the one-step prepared film are aligned. The self-polarization of the prepared film is attributed to a hydrogen bond induced layer-by-layer electrostatic self-assembly growth mechanism. The method is simple, low cost, high efficient, high capability to produce thick and large-area film with smooth morphology and ease to be scalized.

One-step solution casting method for preparing polyvinylidene fluoride-based pyroelectric polymer film

A three-layer self-healing flexible strain sensor includes: a self-healing sensitive layer, wherein a self-healing encapsulating layer is respectively placed on an upper surface and a lower surface of the self-healing sensitive layer. The self-healing sensitive layer comprises a doped carbon material or a conductive composite. The three self-healing layers of the self-healing strain sensor can quickly repair the internal and external damage caused by the layered structure in a short period of time after the external damage, and does not require external stimulation. The three-layer self-healing structure strain sensor is simple in preparation without using a repair agent, which can achieve rapid self-repair at the room temperature, and can be repeatedly repair. The three-layer self-healing structure increases the strength and modulus of the strain sensor as well as increases the ability of the strain sensor to resist external damage.

Three-layer self-healing flexible strain sensor and preparation method thereof

A method for preparing a pyroelectric polymer film based on a combined process of solution casting and uniaxial stretching is disclosed. The pyroelectric polymer film is firstly prepared by solution casting, afterwards, the casted film is subjected to uniaxial stretching when the film is in a semi-cured state (wet film). Thus a larger stretching ratio (&#x3e;10) at a lower temperature (even at room temperature) is realized. Without undergoing a further poling process, the as-stretched film does have a fairly, good pyroelectric performance. Moreover, the surface of the stretched film is smoother and has fewer surface defects.

Method for preparing pyroelectric polymer film based on combined process of solution casting and uniaxial stretching

A carbon material-polymer strain sensitive film and its preparation method are disclosed. The carbon material-polymer strain sensitive film includes multiple layers of carbon sensitive films and multiple layers of polymer films, wherein the multiple layers of carbon sensitive films and the multiple layers of polymer films form a multi-layer composite film in sequence through a layer-by-layer assembly process. The preparation method includes steps of: cleaning, processing a hydrophilic treatment and processing a hydrophobic treatment on a rigid substrate in sequence; preparing a carbon material in dispersion solution and a polymer dispersion solution; through a layer-by-layer self-assembly process, growing the polymer and the carbon material in a form of layer-by-layer on the rigid substrate; transferring the composite film from the rigid substrate to a flexible substrate; and pasting two electrodes at two ends of the composite film and encapsulating with a flexible film.

Carbon material-polymer strain sensitive film and its preparation method

A wavy micro gas chromatography column includes a silicon substrate and a bonded glass cover. A micro channel having a rectangular cross section is etched on the silicon substrate and coated with a stationary phase film. A projection figure of the micro channel on the silicon substrate includes multiple regular wavy curves. Each wavy curve is formed through alternately connecting first upper arcs with first lower arcs. Because the groove has a curving structure, the carrier gas velocity is decreased as the increase of the arc angle, resulting in an improvement of the flow uniformity at the zones between two adjacent bends but also an enlarging nonsymmetric distribution at the bends. Thus, an optimal curving structure can make the overall flow more even, and in turn achieve a better separation performance compared to the straight channel columns. Meanwhile, a wavy channel realizes a longer column length on a given area.

Wavy micro gas chromatography column

A double-sided diaphragm micro gas-preconcentrator has a micro-gas chamber which is formed by stacking an upper silicon substrate with a lower silicon substrate with a back-on-face configuration. One or more suspended membranes are provided on every silicon substrate. The silicon where the suspended membrane is provided is completely removed for forming a cavity. A thin-film heater is deposited on every suspended membrane. A sorptive film is coated on an inner wall of every suspended membrane. Thus, the upper and lower sides of the preconcentrator in the present invention are suspended membranes, which improve the area of the sorptive film on the diaphragm. As a result, the preconcentrating factor is improved while keeping the small heat capacity, fast heating rate, and low power consumption features of the planar diaphragm preconcentrator.

Double-sided diaphragm micro gas-preconcentrator with a back-on-face configuration

A double-sided diaphragm micro gas-preconcentrator has a micro-gas chamber which is formed by bonding an upper silicon substrate with a lower silicon substrate. One or more suspended membranes are provided on every silicon substrate. The silicon where the suspended membrane is provided is completely removed for forming a cavity. A thin-film heater is deposited on every suspended membrane. A sorptive film is coated on an inner wall of every suspended membrane. Thus, the upper and lower sides of the preconcentrator in the present invention are suspended membranes, which improve the area of the sorptive film on the diaphragm. As a result, the preconcentrating factor is improved while keeping the small heat capacity, fast heating rate, and low power consumption features of the planar diaphragm preconcentrator.

Double-sided diaphragm micro gas-preconcentrator

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Sichuan, China

Xiaosong Du