查找使用阿拉丁产品的科研文献

Enhanced the thermal conductivity of PDMS composites under cyclic compression or thermal-oxidative aging through incorporating BN and SiC hybrid fillers

Shufen Han,Xue Ke,Gang Lu,Feng You,Xueliang Jiang,Yanhong Sun,Yunhui Wu,Pei Zhao

Polydimethylsiloxane (PDMS) is an important thermal interface materials in electronic packaging industry with the aid of incorporating thermal conductive fillers. However, the thermal conductivity of PDMS composites is easily affected by outside thermal aging or force field. Herein, hybrid fillers containing boron nitride (BN) and silicon carbide (SiC) or silicon carbide nanowires (SiCNW) were used to construct stable thermal conductive pathways in PDMS matrix under cyclic compression or thermal-oxidative aging conditions. The optimum weight ratio of BN to SiC or SiCNW is 9:1 to obtain high thermal conductivity in PDMS. The thermal conductivity of BN 9 /SiC 1 /PDMS and BN 9 /SiCNW 1 /PDMS composites are slightly decreased by 4.50 and 4.20%, respectively after 64 h of thermal-oxidative aging when the mass ratio of BN to SiC or SiCNW is 9:1. Higher load bearing capacity of BN 9 /SiCNW 1 /PDMS composite can guarantee the good stability of thermal conductivity under cyclic compression. The thermal conductivity of BN 9 /SiCNW 1 /PDMS composite material is increased from 0.96 to 1.12 W m −1  K −1 , with a growth rate of 16.60% after 30 cycles of 1000 N compression, while the thermal conductivity of the BN/PDMS composite is decreased under the same compression conditions. Mechanisms of the cyclic compression effect on the variation of structure and thermal conductivity were proposed. This indicates that BN and SiC hybrid filled polymer composites could maintain high thermal conductivity under thermal-oxidative aging or cyclic compression.

Fluorine-free photothermal superhydrophobic PDA-modified graphene oxide/PDMS coatings enabled by laser-induced hierarchical structures for efficient anti-/de-icing

Qixun Li,Siyan Yang,Lin Zhang,Rongfu Wen,Xuehu Ma

Ice accumulation on outdoor engineering surfaces threatens operational safety in cold and humid environments, creating a need for durable coatings that combine passive anti-icing with active de-icing. Photothermal superhydrophobic coatings are promising, but their practical use is often constrained by fluorinated modifiers, weak coating adhesion, and the difficulty of achieving controllable and durable hierarchical surface structures. Here, we report a fluorine-free photothermal superhydrophobic PDA@GO/PDMS coating with laser-induced hierarchical micro/nanostructures. Polydimethylsiloxane (PDMS) provides a fluorine-free low-surface-energy matrix, while polydopamine-modified graphene oxide (PDA@GO) acts as an interfacially compatible photothermal component. Laser etching removes the resin-rich surface layer and generates hierarchical micro/nanostructures. These structures promote a low-adhesion Cassie–Baxter wetting state and create light-trapping microcavities that enhance multiple scattering and photothermal absorption. After optimizing the laser frequency, scanning speed, and scan repetition, the coating achieves a water contact angle of approximately 164° and a sliding angle below 5°. The laser-induced hierarchical structure prolongs droplet freezing to approximately 712 s and suppresses ice accretion under freezing rain conditions. Under 1 sun irradiation at −15 °C, the laser-etched coating heats to 12.3 °C within 300 s, and its efficient photothermal response combined with low ice adhesion enables rapid photothermal de-icing. The coating also maintains water repellency after mechanical damage, chemical exposure, UV aging, outdoor weathering, and repeated frosting/defrosting cycles, while showing applicability to various substrates and contaminated environments. This work demonstrates a durable fluorine-free strategy for developing laser-structured PDA@GO/PDMS coatings for photothermal anti-icing and de-icing applications.

Ultrathin asymmetric ZnFe-LDH/PDMS flexible sensor for accurate gesture recognition and high-stability human motion monitoring via geometry-embedded algorithm

Jingjie Wang,Mingcong Tang,Xiaoli He,Shaoyang Zhen,Fir Dunkin,Zhaofeng Wu

The urgent need for advanced human-motion sensing in sports and healthcare drives the development of flexible piezoelectric sensors. This study introduces a high-performance, potentially eco-friendly sensor using ultrathin asymmetric ZnFe-LDH nanosheets and PDMS, exhibiting exceptional sensitivity with a pressure sensitivity of 2.316 mV/kPa and an ultra-low detection limit of 0.001 N, along with robust cycling stability (>10,000 cycles). It enables real-time monitoring of subtle motions like nodding and joint bending, and facilitates distinguishable detection of gait and hand gestures via insole and gesture recognition systems. A geometry-driven approach with hyperspherical embedding algorithm is employed for data processing, where multi-granularity temporal convolutions extract features mapped onto a hypersphere for angular similarity-based classification. This achieves 100% gesture and gait recognition accuracy via Geometry-Embedded algorithm. This work provides a low-cost, sustainable material platform and an algorithmic solution for flexible piezoelectric sensing in health monitoring and human-computer interaction, highlighting the transformative potential of ZnFe-LDH/PDMS composites for next-generation flexible electronics.

Multi-Hierarchically Constructing Durable and Flame Retardant CNF/MXene/PDMS Composite Aerogels for Superhigh Electromagnetic Shielding Performance and Ultralow Thermal Conductivity

Yongqian Shi,Yanjun Zhu,Shan Liu,Libi Fu,Juntian Chen,Jiawen Liu,Longcheng Tang,Jiefeng Gao,Pingan Song

There is a significant increase in the demand for lightweight and compressible electromagnetic interference (EMI) shielding materials in various fields. Though MXene aerogels hold immense potential as EMI shielding materials, several shortcomings including poor water resistance, low mechanical robustness, easy oxidation, and high cost limits of their wide application. This work reported a novel strategy involving the co-assembly of MXene and cellulose nanofibers (CNF) through directional freezing and freeze-drying, followed by the capsulation-concreting of a thin layer of flame-retardant polydimethylsiloxane (PDMS) onto the aerogel, to multi-hierarchically construct a series of high-performance CNF/MXene/PDMS composite aerogels. The lightweight CNF/MXene/PDMS/MPP-Zr@PDA composite aerogel achieved ultrahigh EMI shielding effectiveness of 96.8 dB (X-band) and utilization efficiency of 1713.27 dB g g −1 . Furthermore, the PDMS coating effectively imparted excellent compressibility and durability to the 3D scaffold, resulting in a compressive strength of 17.01 kPa for the composite aerogel, representing 199.5% increase compared to CNF aerogel. Additionally, the composite aerogel exhibited outstanding flame-retardant properties (54.6% reduction in heat release rate), ultralow thermal conductivity of 0.0530 W m −1 K −1 and excellent hydrophobicity. Therefore, the durable and flame-retardant CNF/MXene/PDMS composite aerogels hold promising applications in EMI protection, thermal management, smart fire detection, and other specific fields.

Construct a 3D skeleton by bridging graphene nanosheets with soft liquid metal to enhance thermal conductivity of flexible PDMS matrix composites

Ying Zhang,Yuhan Wang,Fufa Zhang,Song Yang,Ting Gu,Fei Liu

Constructing continuous three-dimensional (3D) thermally conductive pathways within the polymer matrix has emerged as a promising strategy to enhance the thermal conductivity of composites. However, the potential benefits of these 3D thermally conductive networks in improving the thermal conductivity performance of composites remain largely unexploited due to significant thermal resistance at the polymer-filler and filler-filler interfaces. Herein, based on the bridging effect during the powder compaction process, flowable liquid metal (LM) and graphene nanoplatelets (GNPs) were selected as thermally conductive fillers. A 3D interconnected polydimethylsiloxane/GNPs/LM (PDMS/GNPs/LM) foam scaffold was fabricated using the salt-template-assisted method, followed by the preparation of corresponding PDMS/GNPs/LM composites through PDMS impregnation and thermal pressure curing. Benefiting from the unique flowability of LM, it infiltrates the gaps between adjacent GNPs during the thermal pressing process, thereby increasing the contact area between fillers and reducing the interfacial resistance at the polymer-filler and filler-filler interfaces. At GNPs and LM loadings of 4.4 wt% and 9.2 wt%, respectively, the thermal conductivity of the PDMS/GNPs/LM composite reaches a value of 1.86 W m −1  K −1 , representing a 322.7 % increase compared to pure PDMS. Finite element simulations confirmed that the bridging effect of LM between adjacent GNPs significantly enhances the heat transfer efficiency of the composite. Furthermore, the composite exhibits outstanding mechanical flexibility, high-sensitivity sensing performance, and excellent hydrophobic properties. This research presents a straightforward and widely applicable method for preparing highly thermally conductive and multifunctional PDMS-based flexible thermal management materials.

Layer-by-layer assembled PI@ZIF-67/PDMS/PEI@ZIF-67 composite membranes with multilayer synergies for efficient H2/CO2 separation

Hang Xu,Lili Jiang,Yan Hu,Jitao Lin,Chao Zhou,Zhijun Zhong,Xiaomin Li,Chuanqiang Yin,Changxin Tang,Lang Zhou

Polyimide (PI) has emerged as a promising material for constructing efficient gas separation membranes due to its excellent stability and gas separation properties. Herein, we report a novel composite membrane structure that utilizes the synergistic effect to achieve efficient H 2 /CO 2 separation by skillfully integrating the advantages of three different functional layers. The support layer consists of a PI fiber membrane loaded with zeolitic imidazolate framework-67 (ZIF-67) using an in-situ growth method, which not only enhances the overall mechanical strength of the membrane, but also provides complex gas transport pathways to improve selectivity. The intermediate layer is made of polydimethylsiloxane (PDMS), which prevents excessive penetration of the selective layer solution into the support layer. The selective layer is a mixed matrix membrane composed of polyetherimide (PEI) as the polymer matrix and zeolitic imidazolate framework-67 (ZIF-67) as the porous filler, which provides critical molecular sieving functionality. Compared to pure polyetherimide (PEI) film, the composite membranes have significantly improved mechanical and gas transport properties, with H 2 permeability of 83.4 Barrer and H 2 /CO 2 selectivity of 5.4. Additionally, the composite membranes exhibit excellent hydrophobicity and thermal stability. Given their outstanding overall performance, the composite membranes developed in this study demonstrate significant potential for CO 2 capture and H 2 recovery applications.

Quantification of uric acid concentration in tears by using PDMS inverse opal structure surface-enhanced Raman scattering substrates: Application in hyperuricemia

Jinming Li,Xiaoyu Cui,Xia Yang,Yuting Qiu,Yuzhan Li,Hui Cao,Dong Wang,Wanli He,Yun Feng,Zhou Yang

Hyperuricemia is closely related to a variety of diseases and has been listed as one of the twenty most persistent diseases in the 21st century by the United Nations. Therefore, strengthening the diagnosis of hyperuricemia has become imperative. Here, ordered inverse opal array structures (PAANs) composed of PDMS and gold nanoparticles (AuNPs) have been designed using a bottom-up self-assembly method. The structures exhibit a periodic distribution of hot spots, an enhancement factor (EF) of 4.22 × 10 4 , and a relative standard deviation (RSD) of signal intensity of less than 5%, which can provide high reproducibility of SERS signals. The PAANs substrate is used to detect uric acid in the tears of patients with hyperuricemia, and the limit of detection is 6.03 μM. The significant linear relationship between blood uric acid and tear uric acid indicates that the developed method is a rapid, effective, and non-invasive technique for the determination of uric acid in tears.

Biomimetic Ag/ZnO@PDMS Hybrid Nanorod Array-Mediated Photo-induced Enhanced Raman Spectroscopy Sensor for Quantitative and Visualized Analysis of Microplastics

Zhengdong Zhu,Konghao Han,Yating Feng,Zhihao Li,Anxin Zhang,Tao Wang,Maofeng Zhang,Wei Zhang

Microplastics are persistent pollutants that accumulate in the environment and can cause serious toxicity to mammals. At present, few technologies are able to quantitatively detect chemicals and provide morphological information simultaneously. Herein, we developed a dragonfly-wing-mimicking ZnO nanorod array decorated with AgNPs on polydimethylsiloxane (PDMS) as a surface-enhanced Raman spectroscopy (SERS) and photo-induced enhanced Raman spectroscopy (PIERS) substrate for trace analysis of microplastics. The Ag/ZnO@PDMS hybrid nanorod array endows the sensor with high sensitivity and signal repeatability (RSD ∼ 5.89%), ensuring the reliable quantitative analysis of microplastics. Importantly, when the noble metal–semiconductor substrate was pre-radiated with ultraviolet light, a surprising PIERS was attained, achieving an additional enhancement of 11.3-fold higher than the normal SERS signal. By combining the PIERS technology with the “coffee ring effect”, the sensor successfully discerned microplastics of polyethylene (PE) and polystyrene (PS) at a trace level of 25 μg/mL even with a portable Raman device. It was capable of identifying PS microspheres in contaminated tap water, lake water, river water, and seawater with detection limits of 25, 28, 35, and 60 μg/mL, respectively. The recovery rates of PS microspheres in four water environments ranged from 94.8 to 102.4%, with the RSD ranging from 2.40 to 6.81%. Moreover, quantitative and visualized detection of microplastics was readily realized by our sensor. This portable PIERS sensor represents a significant step toward the generalizability and practicality of quantitative and visual sensing technology.

Flexible Pressure Sensors Based on CB/CNTS at PDMS for Wind Pressure Field Monitoring of Cable-Stayed Bridge Using Machine Learning

Yifeng Huang,Yifan Gao,Xiaoming Wang,Wentao Dong,Daojin Yao,Xiao Cheng,Yong Hu

Robust fluorine-free colorful superhydrophobic PDMS/NH2-MIL-125(Ti)@cotton fabrics for improved ultraviolet resistance and efficient oil–water separation

Yang Yingying,Huang Wei,Guo Zengpei,Zhang Shiyu,Wu Feng,Huang Jingjing,Yang Hongjun,Zhou Yingshan,Xu Weilin,Gu Shaojin

Abstract Superhydrophobic cotton fabrics with improved ultraviolet resistance were prepared via in situ growing NH 2 -MIL-125(Ti)(Ti-MOF) nanoparticles on cotton fibers and subsequently coating with polydimethylsiloxane (PDMS) under room temperature. The synergetic effect of Ti-MOFs nanoparticles and PDMS was critical and essential for obtaining a superhydrophobic coating with anti-UV property. The surface microstructure, chemical composition, and superhydrophobic property of the as-prepared fabrics were characterized by K/S value, scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and water contact angle (WCA) measurements. The as-prepared cotton fabrics not merely exhibited desirable superhydrophobic property with a water contact angle (WCA) of 154.7 ± 0.7° and a sliding angle of 3.6°, but also displayed the considerable UV resistance. The oil–water separation, stability of UV protection and superhydrophobicity were also investigated. The superhydrophobicity, anti-ultraviolet property, and K/S value of as-prepared PDMS/Ti-MOFs@cotton fabrics were stable after 300 cycles of abrasion and 5 cycles of washing. The facile synthesis technique provided a simple method for scalable construction of multifunctional fabrics. Graphic abstract

Space-confined growth of 2D MOF sheets between GO layers at room temperature for superior PDMS membrane-based ester/water separation

Li-Hao Xu,Yan Li,Shen-Hui Li,Ming-Yu Lv,Zhi-Ping Zhao

Expanding the metal–organic frameworks (MOFs) category using room-temperature colloidal chemistry route with regular crystal structure is challenging, but important for reducing energy consumption and realizing an economically viable application in industry. Herein, we developed a novel advanced copper terephthalate MOF (CuBDC) between graphene oxide (GO) layers using a simple space-confined growth strategy at room temperature. The inclusion of CuBDC@GO can realize high filler loadings while maintaining uniform dispersion throughout PDMS matrix. The paralled arranged CuBDC sheets created 1D inner vertical channels, along with the enlarged GO interlayer space for rapid molecule permeselective transport. The resultant mixed matrix membranes (MMMs) with 30 wt% CuBDC@GO loading improved the separation factor from 190.6 to 576.3, and simultaneously increased the total flux from 575.2 to 1357.4 g m -2  h -1 for separating 0.5 wt% butyl acetate at 40 °C. The transport mechanism was explained by adjusting the CuBDC content in composites to examine the significant increase in membrane permeability (from 12.5 to 58.3) and selectivity (from 0.7 to 2.0). Compared to alcohol or ketone, the larger size strip-like butyl acetate molecules are ideal for rapid transport through the CuBDC-supported 1D continuous inner channels, and effectively inhibit the movement of water molecules, ultimately resulting in the largest pervaporation performance improvement in butyl acetate/water separation. This CuBDC@GO prepared by a simple, green and room-temperature synthesis route can be widely applied to prepare defect-free membranes with excellent performance for sustainable applications. We also anticipate that this advanced space-confined growth strategy can be extended to various other MOFs and applications.

Durable and flexible Ag-nanowire-embedded PDMS films for the recyclable swabbing detection of malachite green residue in fruits and fingerprints

Juanjuan Luo,Zekai Wang,Yun Li,Changding Wang,Jiefang Sun,Weichun Ye,Xiaolong Wang,Bing Shao

Swab sampling for the trace surface-enhanced Raman scattering (SERS) analysis of an aromatic dye (e.g., malachite green , MG) residue in fruits as well as fingerprints is promising due to its practical utility and efficiency in food security and forensic science. However, the durability and recyclability of the SERS substrates pose an enormous challenge. In this study, a novel flexible film was constructed by embedding a commercial Ag nanowire suspension into a polydimethylsiloxane film (Ag [email protected] ), which simultaneously exhibits SERS activity, durability and recyclability. High SERS performance was still maintained, even against 20 times stretchability, corrosion by HNO 3 , destruction by ultrasonication and a broad working temperature of −20 ℃ to 80 ℃. Excellent recyclability for MG sensing was achieved in ten cycles. Ag [email protected] was successfully used for the quantitative detection of MG in juices of fruits (such as apple and pear) by drop dripping, with a limit of detection of 10 nM and good anti-interference. Meanwhile, the sensitive detection of the MG residue (only 3 ng/cm 2 ) on fruits was enabled by the on-site surface swabbing by recycling for five cycles. Portable detection of the MG residue was further achieved from the 10th fingerprint after successively touching a dye drop onto the functional film combined with a portable Raman spectrometer.