Traditional rigid sensors often lack sufficient flexibility, while pure poly(vinylidene fluoride) (PVDF) piezoelectric materials suffer from limited β-phase content and suboptimal mechanical properties. To address these challenges, we synthesized WO₃@UiO-66-NH₂ heterojunction materials via a hydrothermal method and integrated them with electrospinning technology to fabricate flexible TPU/PVDF composite piezoelectric sensor films. Characterization and performance evaluation identified an optimal PVDF-to-TPU mass ratio of 8:2. Moreover, incorporation of 0.5 wt

Composite piezoelectric fiber films were prepared by growing UiO-66-NO2, Ag/AgCl, and TiO2 on polyacrylonitrile (PAN) through stepwise in situ growth, and this structure was used as the functional layer of a flexible pressure sensor. The loading of UiO-66-NO2 onto the fiber films can be controlled by adjusting the molar mass of metal ions on PAN. By controlling the crystallinity and content of metal-organic framework nanoparticles, Ag/AgCl and TiO2 were synthesized using photoreduction and sol-gel methods, respectively, thereby improving the performance of composite piezoelectric fiber films. The piezoelectric coefficient d(33) of the composite fiber membrane increases from 0.03 pC/N of pure PAN to 11.209 pC/N. The films show good flexibility and a Young's modulus of 1.365 MPa. The sensor boasts an exceptionally high sensitivity, a rapid recovery/response duration of 19 ms/12 ms, and a consistent loading/unloading frequency for a period exceeding 30,000 s of cyclic excitation. Not only that, but the synergistic effect of the ternary components shows excellent inhibitory properties against Staphylococcus aureus. This sensor plays an important role in fields such as human skin antibacterial, human movement monitoring, human medical health, and human energy harvesting.

In this study, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) was used as the matrix, different percentages of Boron Nitride (BN) and Graphene Oxide (GO) were added to P(VDF-HFP), piezoelectric nanofiber films were prepared using electrospinning technology. Through a series of tests, it was determined that the composite film with 2 % BN and 4 % GO exhibited the best piezoelectric effect. The beta-phase content increased from 76.01 %, to 98.48 %. The remanent polarization increased from 0.029 mu C/cm2 to 0. 098 mu C/cm2, BN and GO synergistically enhanced the piezoelectric effect of P(VDF-HFP) film, the presence of GO induces the transformation of BN from multilayer to monolayer, which breaks the inverse symmetry of BN and thus enhances the piezoelectric effect, and the presence of GO increases the flow of electrons between the nanomaterials. While the B atoms in the BN interact with the F atoms in P(VDF-HFP), which promotes the enhancement of the beta-phase in the PVDF-HFP. The piezoelectric film was made into piezoelectric sensor, under a force of 2 N, the piezoelectric output increased from 1.5 V to 7.3 V, the sensitivity increased from 0.722 V kPa-1 to 3.068 V kPa-1. The manufactured piezoelectric sensor exhibits fast response and recovery times (13.66/19.25 ms), after 7000 cycles of testing, the sensor maintained good stability. The developed piezoelectric sensor can detect human motion states, sense the temperature and harvest high-entropy energy to power electronic watches, showing promising potential for applications in smart clothing.

In this study, we have prepared heterostructures with anchored interfacial structures, denoted as MOF@g-C3N4. Through the incorporation of defect engineering, a nitrogen defect induced by g-C3N4 facilitates electron capture, thereby enhancing electron migration between the contact interfaces of the two components. This electron migration generates an internal electric field that effectively augments carrier movement, leading to a marked improvement in the piezoelectric properties of the heterojunction. When MOF@g-C3N4 is incorporated into the PAN macromolecular chain as filler, a flexoelectricity effect is observed. As a result, we have successfully fabricated flexible, high-performance, and multi-functional composite nanofiber films. The piezoelectric sensor developed from this film demonstrates superior dielectric, mechanical, and voltage output attributes, boasting a high dielectric constant of 6.01, an impressive elongation at break of 71.92%, and a sensitivity of 14.53 ​V N−1. By using the signal from the flexible sensor as input, it is possible to display the output waveform to a smart device via the Bluetooth module. This enables precise detection of subtle effects, tracking human outdoor movement, and foreseeing flexible applications in future intelligent electronics. This material presents a novel design and cutting-edge application for binary heterostructures in polymer-based flexible wearable devices.

In this study, we introduce the development and application of a flexible piezoelectric sensor. By incorporating Metal–Organic Framework (UIO-66) and Bi4Ti3O12 into P(VDF-HFP), we fabricated a P(VDF-HFP)/MOF/bismuth vacancy Bi4Ti3O12 composite nanofiber film and undertook comprehensive characterization and performance evaluations. The findings reveal that the PFP-U0.01BKW composite nanofiber thin film demonstrates superior piezoelectric properties, d33 characteristics, mechanical attributes, and heightened sensitivity. Specifically, the PFP-U0.01BKW exhibits a permittivity of 4.34 at 1 kHz, with its elongation at break increasing from 115.1 to 198.8

Flexible sensors, due to their unique advantages, are anticipated to find applications in electronic skin, human monitoring, human–computer interaction, and other fields. Among these, flexible strain sensors have garnered significant attention owing to their broad detection range, high sensitivity, and robust anti-interference capability. This paper presents a method for constructing a uniform conductive network within a thermoplastic polyurethane (TPU) matrix by incorporating ionic liquids (ILs) and carbon black nanoparticles (CB). The resulting flexible strain sensor exhibits sensitivities of 1.16 and 2.15 at 0–60

Layered H-UiO-66@IL composites with both intraparticle micropores, interparticle mesopores, and multiple active sites were prepared. A key aspect of the technique was the addition of deionized water during solvothermal synthesis, which rapidly nucleated layered nanoparticles. A multifunctional, flexible, and stable polyacrylonitrile (PAN)-based membrane was successfully constructed by incorporating H-UiO-66 nanoparticles, modified by ionic liquid (1-allyl-3-butylimidazole tetrafluoroborate), into polymers with macromolecular chains under mild, controlled conditions. The resulting film exhibited excellent dielectric, ferroelectric, and mechanical properties due to the multilayer fiber design. Furthermore, the PAN matrix showed a higher content (97.41 %) of planar zigzag conformations, enhancing the piezoelectric properties. The composite film demonstrated ultra-high sensitivity (10.98 V/N) and an ultra-low detection limit of 3.5 x 10-4 N. In addition, the film passed 1,800-cycle stability tests and maintained its initial output value across various environmental conditions. This flexible piezoelectric sensor shows significant potential for aiding deaf and mute individuals in sign language or breathing communication.

In this study, we present a dual conductive network consisting of a thermoplastic polyurethane (TPU) and polyacrylonitrile (PAN) blend with the addition of MXene and ILs conductive fillers, which ultimately resulted in elastomeric composite fiber membranes by electrospinning technology. Through systematic optimization of the manufacturing process and performance testing, we have validated the superior performance of composite membranes for strain sensing applications. Precise control and optimization of the sensor performance was achieved by controlling the concentration of ILs. The elastomer composite fiber membrane had a dielectric constant of 1811.55 and a conductivity of 10(-6) S/cm at a concentration of 15 % ILs. The fabricated strain sensor achieved a sensitivity of 1.08 with response and recovery times of 93 ms and 95 ms, respectively. In addition, the sensor was able to maintain >2000 stable stretch-release cycles at 133 % strain. The TPAN/MX/ILs strain transducer provides a new methodology and approach to the design and fabrication of multifunctional sensors. It fits the human body well, effectively detects basic joint movements and weak pulse signals, recognizes text signals, and corrects faulty writing habits, thus providing strong support for the development of flexible wearable devices and smart sensing systems.

Traditional living/controlled cationic polymerization provides a simple synthetic route for the preparation of various polymers with set molecular weight, narrow molecular weight distribution, and clear structure. Nowadays, under the requirements of sustainable development, it is very important to explore the green chemical technology in depth. This review offers an overview of initiation systems, reaction media, polymerization techniques, and monomers, with the aim of summarizing environmentally friendly methods utilized in the field of cationic polymerization over the past 15 years. It covers a variety of directions from traditional initiation systems to green initiators, from corrosive solvents to environmentally friendly solvents, from drop initiation to external stimulation initiation, from petroleum fractionated monomers to bio-based monomers. These methods and Techniques aim to develop advanced high-quality polymer products using cationic polymerization, and achieving efficient energy savings and reducing emissions. The ongoing exploration of green-controlled cationic polymerization holds promise for opening up new avenues and novel technology for high-performance polyolefin materials. image

Flexible piezoelectric devices have attracted much attention in the fields of intelligent devices and biomedicine because of their high sensitivity, stability, and flexibility. In this paper, a multifunctional flexible pressure sensor was prepared by adding polyacrylonitrile (PAN) and carboxylic-terminated multi-walled carbon nanotubes (c-MWCNTs) with polyvinylidene difluoride (PVDF) as the substrate. The beta-phase content of PVDF/PAN blended fibers compounded with c-MWCNT was up to 95%. At the same time, when PAN was added, the mechanical properties of the composite fibers were constantly improved. The results show that the polymer blending method can improve the comprehensive properties of PVDF composite. The flexible sensor prepared from the PVDF/PAN/c-MWCNT composite film has an output voltage of 2.1 V and a current of 7 mu A. The addition of c-MWCNT can largely improve the sensitivity of the sensor (4.19 V N-1). The sensor is attached to the finger and shows good output performance under different degrees of bending of the finger. The maximum output voltage of the sensor is 0.4 V, 0.56 V and 1.15 V when the finger bending angle is 30 degrees, 60 degrees, and 90 degrees, respectively. Moreover, the developed piezoelectric sensor can monitor large-scale movements of various parts of the human body. Therefore, this composite material shows potential in areas such as motion monitoring and energy storage devices.

The multilayer composite film system was designed in this study. The multilayer composite film was constructed by alternating electrospinning of MXene doped with polyacrylonitrile (PAN) nanofilm and thermoplastic polyurethane (TPU) nanofilm as piezoelectric functional layer. After utilizing nanofilm material, the piezoelectric sensor was prepared and subsequently examined for its piezoelectric sensitivity, piezoelectric output, and mechanical characteristics. MXene/PAN/TPU multilayer composite films showed good piezoelectric output performance. The final experimental data showed that the piezoelectric sensor of the MXene/PAN/TPU-based system achieved 0.16 kPa−1 piezoelectric sensitivity, 150ms/140ms response time and recovery time, good output voltage and output current, and good output stability. In human biological motion detection, the generator produced a maximum output voltage of 30 V when pressed by the palm. Tests such as palm pressing, finger tapping, and footstomping demonstrated the potential of piezoelectric sensors in human energy harvesting and motion monitoring. Multilayer composite films had flexible mechanical properties and sensitive piezoelectric response and had broad application prospects in piezoelectric sensors and piezoelectric nanogenerators.

In this study, a novel theory called Nanoscale Confinement Polarization Pinning (NCPP) theory is proposed. This theory provides theoretical support for the application of heterojunctions composed of porous metal-organic frameworks (MOFs) and conductors or semiconductors in enhancing the piezoelectric effect of piezoelectric polymers. The heterojunction formed between the metal-organic framework UIO-66(Hf)-NO2 and MoS2 enables the porous MOF to firmly pin the MoS2 onto the molecular chains of PVDF-HFP. During polarization, MoS2, being highly susceptible to the electric field, drives the movement of PVDF-HFP's molecular chains through UIO-66 (Hf)-NO2, this results in the molecular chains of PVDF-HFP aligning along the electric field, leading to a more orderly arrangement of the electric domains within PVDF-HFP and enhancing the piezoelectric effect, with the d33 value increasing from 8 pC N- 1 to 27 pC N- 1. The size of UIO-66(Hf)-NO2 is approximately 50 nm, with a conduction band of -0.93 eV and a bandgap of 2.56 eV, while MoS2 has a size of approximately 400 nm, a conduction band of -0.62 eV, and a bandgap of 1.27 eV. When MoS2 and UIO-66(Hf)-NO2 form a heterojunction, an interfacial electric field is generated at the junction, under the influence of this electric field, the PVDF-HFP molecular chains that penetrate into UIO-66(Hf)-NO2 tend to align, increasing the crystallinity of the composite nanofibers from 29.9 % to 35.0 %. This study broadens the application of heterojunctions formed by porous metal-organic frameworks with other conductors or semiconductors to enhance piezoelectricity, providing theoretical support.

Flexible piezoelectric sensors combine advantages including low-cost, flexibility, multi-functions, present a huge market prospect. In this research, multiwalled carbon nanotubes (MWCNT)/MXene/polyacrylonitrile (PAN) piezoelectric composites films for flexible piezoelectric sensors are fabricated by electrospinning technology, the planar zigzag conformation content of 97.98% in PAN composite fibers is achieved owing to the synergistic effect of MWCNT and MXene, the synergistic effect of MWCNT and MXene nanoparticles can also efficiently promote the mechanical performance and piezoelectric output. The piezoelectric sensor exhibits fast response time (10.21 ms), a possible mechanism is proposed to explain the improvement of piezoelectric effect. The sensor can measure human pulse, distinguish human movements, the fabricated sensor has broad practical value in the field of healthcare, its' use can contribute to stable and accurate measurements of physiological parameters, enabling applications in various healthcare and fitness monitoring scenarios.

As an emerging sensor technology, the flexible piezoelectric sensor has a very wide range of applications. Therefore, in order to achieve better output performance of flexible piezoelectric sensors, it is particularly important to choose piezoelectric materials with good piezoelectric performance. In this study, polyvinylidene difluoride (PVDF)/polyvinyl chloride (PVC)/graphene oxide (GO) composite fibers were fabricated by the electrospinning technique. FTIR and XRD studies showed that the β-phase content of the composite fibers reached 94.6

Wearable sensor technology has garnered increasing attention among researchers. In this study, the porous metal-organic framework containing nitroxide (UIO-66-NO 2 ) is pasted onto MXene by hydrogen bonding and then incorporated into PVDF-HFP for electrospinning to fabricate piezoelectric membranes. The porous structure of the metal-organic frameworks significantly contributes to the alignment of electric domain orientation within the piezoelectric membranes post-polarization, and the nitro of UIO-66-NO 2 helps to enhance the inductive power effect of the sensor, the piezoelectric constant of the composite piezoelectric membrane reaches 26.1 pC/ N, 5.8 times that of the pure PVDF-HFP membrane (4.5 pC/N). The sensitivity reaches 20.99 V/N, which is 5.75 times that of the pure PVDF-HFP sensor (3.65 V/N). We conduct an exploration into the potential mechanisms behind the enhanced piezoelectric properties resulting from the incorporation of MXene and the metal-organic framework. The fabricated flexible pressure sensor exhibits commendable cyclic stability, boasting rapid response and recovery time (20/10.8 ms). The sensor demonstrates the capability to monitor human respiration and pulse, discern various parts of the human body and their respective amplitudes, differentiate between different materials, the pressure sensor has potential applications in human-computer interaction and health monitoring.

In this study, a piezoelectric nanogenerator (PENG) based on multilayer composite fiber had good and stable piezoelectric output performance, which could realize biomechanical energy collection and human movement monitoring. The polyvinylidene fluoride-hexafluoryl propylene (P(VDF-HFP)) composite fiber doped with MXene was used as a promising piezoelectric functional layer (MPFP). By electrospinning, P(VDF-HFP) composite fiber was constructed by alternating electrospinning with polyurethane (TPU) nanofibers layer by layer. The adoption of MXene as a functional filler promoted the transformation of P(VDF-HFP) from alpha to piezoelectric beta-crystal, the piezoelectric beta-crystal content of P(VDF-HFP) increased, and the dielectric properties and polarization levels were enhanced. At the same time, the multi-layer structure design improved the piezoelectric sensitivity and mechanical properties of the composite fiber, and the composite fiber was more flexible and had longer tensile strain. With excellent dielectric and mechanical properties, 3MPFP/TPU/3MPFP/TPU multilayer composite fibers showed piezoelectric sensitivity of 10.88 V/kPa. Under the action of palm pressing, the PENG generated an open circuit voltage of 25 V, and the voltage signal of the device under different motion forms had specific characteristics such as peak value, frequency, and shape, which could be used to realize the analysis of human motion forms. This study provided an efficient, simple, and creative new idea for the application of flexible energy storage electronic devices, PENGs, and piezoelectric sensors. High performance flexible piezoelectric nanogenerator. image

In this study, a flexible piezoelectric sensor based on polyacrylonitrile (PAN), zirconium-based MOF (UiO-66) with nitro (NO2) and two-dimensional material MXene composite nanofiber film was proposed. When pressure was applied, the three-dimensional structural nanopores were compressed, increasing the intercalation structure between the MXene nanosheets coated in the fibers. The double-packed system produced a higher resistance change under the same pressure load, which can be explained by the fact that the low-conductivity octahedral UiO-66-NO2 particles acted as a similar "buffer" between the highly conductive MXene. At the same time, a large number of hydrogen bonds between the surfaces of the two fillers enhanced the synergistic effect and promoted the interfacial coupling effect, so that more 31-helical conformation in the PAN matrix was converted into a planar zigzag conformation. This improved the piezoelectric performance and enabled the sensor to have a voltage output of about 200 V in the detection range. And because the polyhedral form of UiO-66-NO2 particles provided a rougher surface structure, the piezoelectric sensor can achieve a high sensitivity of 5.62 V/N. The other results showed that the dielectric constant of the designed flexible piezoelectric sensor was increased to 2.67, the dielectric loss was kept at a low level of 0.026, and the maximum elongation was 56.03%. This multi-functional sensor shows great potential in the fields of health and medical treatment, human-computer interaction, etc.

Polyacrylonitrile (PAN) nanofiber-based flexible piezoelectric sensors are recognized for their applicability in wearable electronic devices, personal health monitoring, and motion detection. This research explores the impact of dual fillers, MXene and polydopamine-modified zinc oxide (PDA@ZnO), on the characteristics of PAN-based piezoelectric composite nanofiber films, including planar zigzag conformation content, dielectric, ferroelectric, piezoelectric, and mechanical properties. By integrating PDA@ZnO as a filler, PAN/MXene/PDA@ZnO-5 (PMPO) piezoelectric sensors were developed, showcasing enhanced piezoelectric sensing capabilities. These sensors achieved a sensitivity of 28.56 V/N across a broad linear range, with superior mechanical stability and durability across 3000 loading - unloading cycles, and exhibited swift response and recovery times of 49 ms and 40 ms, respectively. Furthermore, their unique fiber structure and flexibility, when interfaced with the human body, enable the detection of minute physiological movements and the conversion of varied motions into distinct voltage outputs. Thus, these sensors offer considerable promise for applications in human health monitoring and motion posture correction.

Temporal control of chain growth is a central challenge for photoinitiated active polymerization. In this work, we introduced an iridium salt complex-based catalyst system to achieve fine temporal control of the chain growth process. By electrochemical analysis, compared with the pyran salt photocatalyst, it was found that the iridium salt complex could promote the chain transfer of active species to reversible addition-fragmentation chain transfer polymerization (RAFT) reagent, thereby generating dormant species, which provided the possibility of time control of the polymerization process. Using this catalytic system, we successfully achieved homopolymerization of vinyl ethers with different substituents and random copolymerization with isobutyl vinyl ethers, which is not only pointed the way for broadening the monomer selection in the future, but also provided an innovative way to prepare new functionalized materials. Iridium complexes catalyze photocontrolled cationic polymerization of alkyl vinyl ether under blue led illumination. image

在工程教育认证背景下,以高分子化学课程为例,全面推进专业课程的思政建设,落实立德树人,从课程大纲修改、课程目标确定、教学设计到教学内容改革等方面开展课程思政.通过课程思政与高分子材料与工程专业人才培养、工程教育认证很好的融合,引导学生在专业课程知识获取的同时,树立科研生产安全观及全局观、树立社会主义核心价值观、坚定"四个自信"、加强环保意识、社会责任,实现专业课与思想政治教育的有机融合.