Abstract:
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 (>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 having less surface defects.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.