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It is highly demanded to understand the confinement effect on nanoconfined polymers. Recent studies reported a strong perturbation of local dynamics and substantial alteration of glass transition temperature Tg at nanoscale. However, how confinement affects the mechanical properties of polymers is not fully understood. Here, we show that the modulus of thin polymer films could be remarkedly altered through a polymer–polymer interface. The modulus of a thin polystyrene (PS) film next to a polydimethylsiloxane (PDMS) was determined from the PS–PDMS bilayer bulging test. A series of experiments show that the modulus of PS can be increased up to 37%, when the modulus of the neighboring PDMS varies from 1.04 to 4.88 MPa. The results demonstrate a strong sensitivity of mechanical properties of thin polymers to the hard/soft environment, which we attribute to the change of high-mobility layer by the polymer–polymer interface. [ABSTRACT FROM AUTHOR]

The rapid realization of efficient anti-icing coatings on diverse substrates is of vital value for practical applications. However, current approaches for rapid preparations of anti-icing coatings are still deficient regarding their surface universality and accessibility. Here, we report a simple processing approach to rapidly form icephobic liquid-like polydimethylsiloxane (PDMS) brushes on various substrates, including metals, ceramics, glass, and plastics. A poly(dimethylsiloxane), trimethoxysilane is applied as a reactant under the catalysis of a minimal amount of acid formed by hydrolysis of dichlorodimethylsilane. With such an advantage, this approach is approved to be applicable of coating metal surfaces with less corrosion. The distinctive flexibility of the PDMS chains provides a liquid-like property to the coating showing low contact angle hysteresis and ice adhesion strength. Notably, the ice adhesion strength remains similar across a wide temperature window, from −70 to −10 °C, with a value of 18.4 kPa. The PDMS brushes demonstrate perfect capability for resisting acid and alkali corrosions, ultra-violet degradation, and even tens of icing/deicing cycles. Moreover, the liquid-like coating can also form at supercooling conditions, such as −20 °C, and shows an outstanding anti-icing/deicing performance, which meets the in situ coating reformation requirement under extreme conditions when it is damaged. This instantly forming anti-icing material will benefit from resisting instantaneous ice accretion on surfaces under extremely cold conditions. [ABSTRACT FROM AUTHOR]

Many modern anti-icing and anti-fouling coatings rely on soft, low surface energy elastomeric materials such as polydimethylsiloxane for their functionality. While the low surface energy is desirable for reducing adhesion, very little work considers the larger contribution to adhesive failure caused by the viscoelastic nature of elastomers. Here we examine several different siloxane elastomers using a JKR adhesion test, which was operated over a range of different speeds and temperatures. Additionally, we characterize the dynamic mechanical modulus over a large range of frequencies for each material. We note that surface energies of the materials are all similar, but variation in adhesion strength is clear in the data. The variation at low speeds is related to elastomer architecture but the speed dependence itself is independent of architecture. Qualitative correlations are noted between the JKR adhesion measurements and the dynamic moduli. Finally, an attempt is made to directly compare moduli and adhesion through the recent Persson–Brener model. Approximations of the model are shown to be inaccurate. The full model is found to be accurate at low speeds, although it fails to precisely capture higher speed behaviour. [ABSTRACT FROM AUTHOR]

Heat exchangers are made of metals because of their high heat conductivity and mechanical stability. Metal surfaces are inherently hydrophilic, leading to inefficient filmwise condensation. It is still a challenge to coat these metal surfaces with a durable, robust, and thin hydrophobic layer, which is required for efficient dropwise condensation. Here, we report the nonstructured and ultrathin (∼6 nm) polydimethylsiloxane (PDMS) brushes on copper that sustain high-performing dropwise condensation in high supersaturation. Due to the flexible hydrophobic siloxane polymer chains, the coating has low resistance to drop sliding and excellent chemical stability. The PDMS brushes can sustain dropwise condensation for up to ∼8 h during exposure to 111 °C saturated steam flowing at 3 m·s-1, with a 5-7 times higher heat transfer coefficient compared to filmwise condensation. The surface is self-cleaning and can reduce the level of bacterial attachment by 99%. This low-cost, facile, fluorine-free, and scalable method is suitable for a great variety of heat transfer applications.

Rapid, simultaneous detection of organic chemical pollutants in water is an important issue to solve for protecting human health. This study investigated the possibility of developing an in situ reusable optical sensor capable of selective measurements utilizing a chalcogenide transducer supplemented by a hydrophobic polymer membrane with detection based on evanescent waves in the mid-infrared spectrum. In order to optimise a polyisobutylene hydrophobic film deposited on a chalcogenide waveguide, a zinc selenide prism was utilized as a testbed for performing attenuated total reflection with Fourier-transform infrared spectroscopy. To comply with the levels mentioned in health guidelines, the target detection range in this study was kept rather low, with the concentration range extended from 50 ppb to 100 ppm to cover accidental pollution problems, while targeted hydrocarbons (benzene, toluene, and xylene) were still detected at a concentration of 100 ppb. Infrared measurements in the selected range showed a linear behaviour, with the exception of two constantly reproducible plateau phases around 25 and 80 ppm, which were observable for two polymer film thicknesses of 5 and 10 μm. The polymer was also found to be reusable by regenerating it with water between individual measurements by increasing the water temperature and flow to facilitate reverse exchange kinetics. Given the good conformability of the hydrophobic polymer when coated on chalcogenide photonic circuits and its demonstrated ability to detect organic pollutants in water and to be regenerated afterwards, a microfluidic channel utilising water flow over an evanescent wave optical transducer based on a chalcogenide waveguide and a polyisobutylene (PIB) hydrophobic layer deposited on its surface was successfully fabricated from polydimethylsiloxane by filling a mold prepared via CAD and 3D printing techniques. [ABSTRACT FROM AUTHOR]

Hydrophobized soils have functional hydrophobic coatings to delay or restrict water infiltration and thus prevent infrastructure failure and long-term degradation. Over time, hydrophobized soils will be subjected to degradation under the action of external stresses, leading to the loss of its functional properties. Microencapsulation approaches, initially developed for self-healing applications emerge as a potential solution to enhance, switch (from hydrophilic) or prolong the longevity of hydrophobized soils. The aim of this study is to produce and investigate the effectiveness of microencapsulation to impart hydrophobicity in granular materials in response to external stimuli. In this research, polydimethylsiloxane (PDMS), with hydrophobic properties, is encapsulated in calcium alginate microcapsules with the ionic gelation method. The effectiveness of the microcapsules to induce hydrophobicity is investigated by mixing sand with microcapsules and quantifying the change of the contact angle and water drop penetration time (measures of hydrophobicity) under an external trigger, i.e., under drying and consecutive wetting–drying cycles. The results show that microcapsules release the hydrophobic cargo (PDMS) during shrinkage. After drying, the PDMS content in sand increased to 0.1–0.8% by mass of sand. The released hydrophobic cargo (PDMS) induced hydrophobicity in sands, reflected by a contact angle increase from 29.7° to at least 87.7°. The amount of polydimethylsiloxane encapsulated is a key parameter controlling the release of hydrophobic cargo. In addition, 4% capsule content in sands is identified as an effective microcapsule content in inducing hydrophobicity. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane (PDMS) is widely used in biomedical applications due to its biocompatibility and flexibility but faces challenges due to its hydrophobicity and limited mechanical strength. This study explores the incorporation of thyme (Thymus vulgaris L.) into PDMS to enhance its properties for wound dressing applications. PDMS composites containing 2.5 wt.% and 5 wt.% of thyme were prepared and evaluated for physical, chemical, mechanical, and biological properties. Scanning electron microscopy, contact angle measurements, absorption tests, Fourier-transform infrared spectroscopy, differential scanning calorimetry, hardness, tensile testing, antibacterial activity, and cell viability assays were conducted. Thyme integration improved mechanical properties with increased absorption and preserved hydrophobicity. FTIR and DSC analyses indicated minimally altered crystallinity and chemical interactions. Hardness decreased with higher thyme content due to terpene-induced polymerization inhibition. Tensile testing showed reduced stress at break but increased elongation, suitable for wound dressings. Enhanced antibacterial activity was observed, with composites meeting bacteriostatic standards. Cell viability exceeded 70%, with optimal results at 2.5 wt.% thyme, attributed to cytokine-inducing compounds. Thyme-incorporated PDMS composites exhibit improved antibacterial and mechanical properties, demonstrating the potential for advanced wound dressings. [ABSTRACT FROM AUTHOR]

A Mach-Zehnder interferometer (MZI) sensor based on thin-core fiber (TCF) is proposed. Sensitive materials such as polydimethylsiloxane (PDMS) or gelatin are coated on the surfaces of MZIs to achieve temperature, pressure, and humidity measurements. MZI is composed of single mode fiber (SMF), TCF, and multimode fiber (MMF) spliced together to form a "SMF-MMF-TCF-MMF-SMF" structure. The core/cladding diameters of TCF are 3.8 µm and 80 µm respectively. When three types of optical fibers with different core diameters are cascaded together, many cladding modes are excited to form MZI. Firstly, two similar MZI structures were fabricated designated by MZI1 and MZI2. In order to improve the sensitivity and mechanical strength, a layer of PDMS film was coated on the TCF surface of MZI1. Then, a layer of gelatin film is covered on the TCF surface of MZI2. PDMS has the high thermal expansion coefficient, thermal optical coefficient, and elasticity, and gelatin has good humidity sensitivity properties. The experimental results showed that the temperature and pressure sensitivity of MZI1 coated with PDMS reached −340 pm/°C and −14.3 nm/MPa, respectively, while the humidity sensitivity of MZI2 coated with gelatin reached −112.57 pm/% RH. When a fiber Bragg grating is cascaded with the MZI1, the sensor can achieve simultaneous measurement of temperature and pressure, eliminating crosstalk. The proposed sensor has an extremely simple structure and manufacturing method, which only involves the splicing of optical fiber and the coating by the film. In addition, the proposed sensor has a robust structure, good repeatability and stability, and high sensitivity, which has broad application prospects. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane has the characteristics of low-temperature flexibility and excellent aging resistance. However, high molecule mobility and weak interactions between PDMS molecules result in poor mechanical strength and deficient gas barrier properties of PDMS composites. Herein, diamino-polydimethylsiloxane (PDMS) was reacted with 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) to form urea-carbamate functionalized PDMS (MDI-PDMS-BDO) with different hard segment contents. Furthermore, the modified graphene oxide (iGO) was obtained by the reaction between graphene oxide (GO) and MDI. iGO was further introduced into the functionalized PDMS to prepare iGO/urethane-urea functionalized PDMS composites (iGO/MDI-PDMS-BDO). An ordered structure was formed by the hard segments of the MDI-PDMS-BDO functionalized PDMS. A strong urea-based interface was also obtained between iGO and functionalized PDMS. iGO became the cross-linking center in the iGO/MDI-PDMS-BDO composites. Due to the ordered structure of hard segments and the iGO network formed in the PDMS composite with only 0.07 wt% iGO, the tensile strength and gas barrier properties of the iGO/MDI-PDMS-BDO composite were increased by 18 times and 64.27%, respectively, compared with pure PDMS. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effect of sodium picosulfate/magnesium citrate (SPMC) and 3 L split-dose polyethylene glycol (PEG) with or without dimethicone on bowel preparation before colonoscopy. Methods: In this multicenter, prospective, randomized, controlled study conducted from April 2021 to December 2021, consecutive adult patients scheduled for colonoscopy were prospectively randomized into four groups: SPMC, SPMC plus dimethicone, 3 L PEG, and 3 L PEG plus dimethicone. Primary endpoint was colon cleansing based on Boston Bowel Preparation Scale (BBPS). Secondary endpoints were bubble score, time to cecal intubation, adenoma detection rate (ADR), patient safety and compliance, and adverse events. Results: We enrolled 223 and 291 patients in SPMC and 3 L PEG group, respectively. The proportion with acceptable bowel cleansing, total BBPS score and cecal intubation time were similar in all four subgroups (p > 0.05). Patient-reported acceptability and tolerability was significantly greater in SPMC than 3 L PEG group (p < 0.001); adverse events were significantly lower in SPMC than latter group (p < 0.001). ADR in both groups was greater than 30%. Conclusion: SPMC had significantly higher acceptability and tolerability than 3 L PEG, however, was similar in terms of bowel-cleansing effect and cecal intubation time and hence can be used before colonoscopy preparation. [ABSTRACT FROM AUTHOR]

Guided nanowires grown on polymer surfaces facilitate their seamless integration as flexible devices without post‐growth processing steps. However, this is challenging due to the inability of polymer films to provide the required lattice‐matching effect. In this work, this challenge is addressed by replicating highly aligned nanogrooves from a compact disc (CD) onto a casted flexible polydimethylsiloxane (PDMS) surface. Leveraging the replicated nanogrooves, copper hexadecafluorophthalocyanine (F16CuPc) and various metal phthalocyanines are guided into large‐area, self‐aligned nanowires. Subsequently, by employing specifically designed shadow masks during electrode deposition, these nanowires are seamlessly integrated as either a monolithic flexible photodetector with a large sensing area or on‐chip flexible photodetector arrays. The resulting flexible photodetectors exhibit millisecond and long‐term stable response to UV–vis–NIR light. Notably, they demonstrate exceptional bending stability, retaining stable and sensitive photoresponse even at a curvature radius as low as 0.5 cm and after enduring 1000 bending cycles. Furthermore, the photodetector array showcases consistent sensitivity and response speed across the entire array. This work not only proves the viability of guided nanowire growth on flexible polymer surfaces by replicating CD nanogrooves but also underscores the potential for large‐scale monolithic integration of guided nanowires as flexible devices. [ABSTRACT FROM AUTHOR]

Photocuring 3D printing of materials exhibiting high fracture toughness and excellent mechanical properties (flexural strength/modulus) is challenging. Nowadays, most of the photocurable 3D printing resins are based on a mixture of multifunctional (meth)acrylates and provide therefore brittle materials. This article describes further developments of a toughening strategy based on the incorporation of block copolymers in low crosslink density methacrylate‐based materials. Six dimethacrylates bearing a bisphenol A core and urethane groups are successfully synthesized. Various spacers between the bisphenol A core and the methacrylate groups are selected. Each monomer is combined with (octahydro‐4,7‐methano‐1H‐indenyl)methyl acrylate as a monofunctional monomer and a poly(ε‐caprolactone)‐polydimethylsiloxane‐poly(ε‐caprolactone) triblock copolymer is added as toughener. It is shown that the addition of the triblock copolymer results for all mixtures in a strong increase of the fracture toughness. Moreover, the higher the amount of monofunctional monomer, the stronger the increase. The nature of the urethane dimethacrylate is found to have a significant influence on the fracture toughness, flexural strength, and flexural modulus of cured materials. Two of the synthesized dimethacrylates are identified as promising candidates for the development of fracture‐tough photocuring 3D printing materials. [ABSTRACT FROM AUTHOR]

The potential applications of stretchable strain sensors in wearable electronics have garnered significant attention. However, developing susceptible stretchable strain sensors for practical applications still poses a considerable challenge. The present study introduces a stretchable strain sensor that utilizes silver nanowires (AgNWs) embedded into a polydimethylsiloxane (PDMS) substrate. The AgNWs have high flexibility and electrical conductivity. A stretchable AgNW/Pat-PDMS conductive film was prepared by arranging nanowires on the surface of PDMS using a simple rod coating method. Depending on the orientation angle, the overlap area between nanowires varies, resulting in different levels of separation under a given strain. Due to the separation of the nanowire and the change in current path geometry, the variation in strain resistance of the sensor can be primarily attributed to these factors. Therefore, precision in strain regulation can be adjusted by altering the angle θ (0°, 60°, or 90°) of the nanowire. At the same time, the stability of the AgNW/Pattern-PDMS (AgNW/Pat-PDMS) conductive film application was verified by preparing a sandwich structure PDMS/AgNW/Pat-PDMS stretchable strain sensor. The sensor exhibited high sensitivity within the operating sensing range (gauge factor (GF) of 15 within ~120% strain), superior durability (20,000 bending cycles and 5000 stretching cycles), and excellent response toward bending. [ABSTRACT FROM AUTHOR]

Multifunctional integration is a pivotal aspect in the development of flexible sensors that facilitate augmented interaction with the physical environment. However, contemporary multifunctional flexible sensors face challenges arising from their complex structures and high costs. Therefore, polydimethylsiloxane (PDMS) /liquid metal (LM) films with a hierarchical structure prepared via the gravity‐induced deposition of LM are applied to multifunctional flexible sensors. PDMS/LM films exhibit remarkable flexibility and function as flexible electrodes for pressure sensors as well as a single‐electrode mode triboelectric nanogenerator (TENG). The porous PDMS/carbon nanotube (CNT) dielectric with an array structure is developed for pressure sensing, showing commendable sensitivity (0.671 kPa−1) even under low pressures (0–17 kPa). Compared with solid and porous dielectrics, its sensitivity is improved over the entire pressure range. The sensor achieves a response time of ≈80 ms and demonstrates exceptional stability. Furthermore, when the PDMS/LM film with a hierarchical structure functions as a TENG, it can serve as a self‐powered sensor for measuring dynamic forces and aid in material recognition with the assistance of capacitive pressure sensing. This study provides a new perspective on the simplified design and integration of multifunctional flexible sensors. [ABSTRACT FROM AUTHOR]

Mechanically driven light generation is an intriguing phenomenon holding great promise in various fields. However, the existing mechanoluminescence (ML) materials always suffer from poor self‐recoverability, low repeatability, and environmental disturbance, severely hindering their practical applications. In this work, a self‐activating ML system based on interfacial triboelectrification is created by compositing the Ca6BaP4O17:0.02Ce3+ powders into a flexible polydimethylsiloxane (PDMS) matrix. With no need for pre‐irradiation, the composite film emits self‐activating and self‐charging ML simultaneously in response to the rubbing or stretching stimuli. Accordingly, the Ca6BaP4O17:0.02Ce3+/PDMS exhibits desirable self‐recovery and repeatable ML performance, which could still be recorded (or observed by naked eyes) even after ca. 1000 stretching cycles with a fast self‐recovery period of < 0.1 s. Furthermore, the Ca6BaP4O17:0.02Ce3+/PDMS possesses good thermal stability in a temperature range from 298 to 473 K. The developed Ca6BaP4O17:0.02Ce3+/PDMS is applicable to various fields, and the dual‐mode information storage and photonic skin devices are created as representatives. Compared to the existing oxide‐based ML materials (the ML signal disappears after only several or tens of rapid mechanics cycles), this work breaks through the bottleneck issues on the self‐recoverability, repeatability, and thermal stability, which significantly advances the ML field. [ABSTRACT FROM AUTHOR]

This study synthesized polydimethylsiloxane (PDMS)‐modified polyaspartate polyurea (PPPU) with different ratios, considering the practical performance requirements of underground water supply pipeline spray repair materials. The successful synthesis of PPPU was confirmed using Fourier transform infrared spectrometer (FTIR) spectroscopy. The influence of the ratio of the two components and the content of α,ω‐aminopropyl terminated polydimethylsiloxane (APT‐PDMS) on the drying time and tensile performance of PPPU coatings was evaluated. Based on this evaluation, a superior ratio for PPPU coatings was proposed. Subsequently, the bonding performance, hydrophobicity, and corrosion resistance of PPPU coatings at the superior ratio were tested. The results indicate that as the mass ratio of polyaspartic acid ester to hexamethylene diisocyanate trimer increases, both the drying time and tensile strength of the coating decrease. The addition of APT‐PDMS results in a decrease in the tensile strength of PPPU, but an increase in its elongation at break. The peak value of elongation at break is achieved when the APT‐PDMS content is 5%, making the PPPU2‐1‐5 coating the superior ratio for spray application on water supply pipelines. Through experiments, it was determined that the bonding strength of the PPPU2‐1‐5 coating with cement mortar under dry and humid conditions, static water contact angle (93.4°), and corrosion resistance performance are superior to those of the unmodified polyurea coating, demonstrating its application advantages. The conclusions drawn in this study provide a theoretical foundation for the practical engineering application of PPPU. [ABSTRACT FROM AUTHOR]

Environmentally friendly high‐performance composites made from either reprocessable polymer matrix or renewable fillers have become increasingly significant in order to reach a sustainable future. Herein, polydimethylsiloxane/modified cellulose nanocrystals (PDMS/mCNC) composites showing outstanding mechanical and reprocessable properties via silyl ether linkages are prepared. With only 1 wt% mCNC, the PDMS/mCNC composite exhibits the tensile strength of 2.96 MPa, which is twice that of the pure PDMS elastomer, while the toughness can achieve 7.32 MJ m−3. Remarkably, the reprocessing efficiency can be as high as 100% even for triple reprocessing process. Additionally, the favorable effect of mCNC on constructing hybrid filler network within vitrimers is explored for the first time. Selection of boron nitride nanosheet (BNNS) as the functional filler, 40 wt% BNNS is uniformly dispersed by only a small amount of mCNC and a homogeneous thermally conductive network is built, with the thermal conductivity of the PDMS/mCNC@BNNS composite increasing remarkably to 2.901 W m−1 K−1. In a word, this work paves the way to develop sustainable, mechanically strong, and reprocessable composites with mCNC as a renewable bio‐filler. [ABSTRACT FROM AUTHOR]

The combination of 3D‐printing technology and microfluidics has garnered widespread interest for creating new designs and has opened a large window for creativity. However, some laboratories do not have the necessary technology to explore this potential advantage. In this paper, we demonstrate how to explore target technologies to fabricate a single version of a polydimethylsiloxane (PDMS)‐based electroanalytical platform using a low‐cost protocol and disposable materials. This protocol is cost‐effective in terms of equipment and materials, allowing for the creation of a circular channel, a T‐junction system, and two designs of electrochemical detectors customized onto a single platform. The interesting new device has some important characteristics, such as fabrication following green and sustainable protocols. Additionally, it can address the limitations associated with flow‐based analysis, for which the classical three‐electrode configuration is inadequate. It has also demonstrated the feasibility of using the device in analytical applications for the determination of salicylic acid in commercial dermocosmetic samples, including aqueous samples. [ABSTRACT FROM AUTHOR]

Microfluidics is an area that allows the design and construction of microchips. The most common fabrication of these chips is expensive and difficult to access, requiring a specialized laboratory, with instruments that need to be monitored by experienced technicians and high-cost materials, then new techniques are sought to facilitate their production. Here, we present a fabrication methodology that combines the 3D printer resolution, and the polydimethylsiloxane flexibility to create hydrophobic and biocompatible microfluidics chips which are connected to a microfluidic control system. Transparent, and leak-free polydimethylsiloxane microchips were achieved with a width and a height of 250 µm. This strategy allows to produce at least, 20 chips using the same resin mold. The pressure at which the chip can work is from 2.4 kPa to 124 kPa. This work provides a low-cost alternative for academic and research groups to create their own microfluidic systems and use the microfluidic advantages in all types of applications including biosensor building, studies in medicine, biology, nanoscience, environmental technology, chemistry, etc., since it allows a controlled manipulation of one or more fluids in a certain area where a sensor can be placed, generate a reaction, among others. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the morphology of ionic poly(dimethylsiloxane) silica nanocomposites of randomly grafted or chain-end-functionalized ionic PDMS melts using atomistic MD simulations. The localization of the charge alters the structure and dynamics of ionic PDMS chains near the nanosilica surface. The chain-end ionic PDMS obtains the largest dimensions, whereas the charge fraction of 10% of the random ionic copolymers leads to a contraction of PDMS chains. The charge fraction dramatically alters the dynamics of the ionic PDMS chains, although they reach the diffusive regime. An anisotropy of PDMS chain dynamics perpendicular and parallel to the nanosilica and an heterogeneity of PDMS dynamics from the nanosilica surface are observed for the longer randomly grafted and chain-end ionic PDMS chains. The longer randomly grafted ionic PDMS chains are strongly adsorbed in the vicinity of the nanosilica surface. [ABSTRACT FROM AUTHOR]

Strategies for synthesis and processing of silicone rubber materials in three-dimensional (3D) structures are of significant interest based on their exceptional potential in many applications including flexible electronics and biomedical devices. Here, we present a synthetic approach of crosslinked polydimethylsiloxane (PDMS) exhibiting dynamic siloxane bond exchange for sufficient stress relaxation capability to enable versatile processabilities including reprocessing, remolding, self-healing, and hot-melt extrusion 3D printing. Considering the significant potential of recyclable silicone materials and their 3D structures, presented approaches enabled by dynamic exchangeable PDMS can provide a new pathway to replace conventional unrecyclable silicone used in diverse industrial sectors. [ABSTRACT FROM AUTHOR]

Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta. [ABSTRACT FROM AUTHOR]

An optimal portable microfluidic device should ensure least number of accessories for versatile field application. Typically, in such a device fabricated with polydimethylsiloxane (PDMS), the transport of fluid is enabled through a nonconventional pumping mechanism. This pumping system has been demonstrated to utilize the relatively high air permeability of polydimethyl siloxane (PDMS) to transport small volume fluid. In the recent past, microporous PDMS has replaced PDMS in this capacity. Microporous PDMS is typically fabricated through a series of steps where a sacrificial template is used to infiltrate the polymer. This template is removed after the polymer undergoes curing. This method has consistently produced a spongy structure that is nonrigid, sticky, and moist rendering it unwieldy. In this work, we present a novel concept of using camphor (Cinnamomum camphora) as a template to fabricate a dry polymeric sponge. The proposed sponge is molded on a sublimable material, camphor to avoid the additional step of template dissolution. The sponge is demonstrated to be stiff yet flexible rendering it convenient to be compacted into a confined space. Additionally, the sponge is dry and nonsticky as compared to structures that have been generated through sugar leaching. [ABSTRACT FROM AUTHOR]

Preparing asymmetric pervaporation membranes is a kind of promising method to enhance pervaporation membrane flux. Hydrophobic PVDF polymer can be used to prepare asymmetric pervaporation membranes, but its separation factor is relatively low. In this work, to improve the performance of PVDF membrane pervaporation, PDMS polymer was added to the PVDF membrane, and asymmetric PDMS/PVDF permeable membranes were prepared by the non‐solvent induced phase separation (NIPS) method. The effects of mass ratios of PDMS to PVDF on the membrane structures and the membrane properties were characterized by SEM, XRD, FTIR, TGA, water contact angle and mechanical strength. The results showed that the ratios of the PDMS: PVDF affect its phase‐separation behavior. As the addition of PDMS increased, the finger‐like pores on the membrane section gradually became longer, the upper surface changed from less porous to porous structure, and the lower surface structure changed from interconnected flocculent structure to porous, and the best structure of the blend membrane was achieved when the PDMS: PVDF mass ratio was 1 : 5. Therefore, the membrane had the best separation performance in separating 15 wt. % ethanol aqueous solution with a permeate total flux of 273.65 g/(m2 h) and a separation factor of 9.09 when the mass ratio of PDMS: PVDF was 1 : 5. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of ammonia (NH3) in aqueous electrolyte has long been suffered from poor nitrogen (N2) supply owing to its low solubility and sluggish diffusion kinetics. Therefore, creating a N2 rich microenvironment around catalyst surface may potentially improve the efficiency of nitrogen reduction reaction (NRR). Herein, a delicately designed N2 filtering membrane consisted of polydimethylsiloxane is covered on catalyst surface via superspreading. Because this membrane let the dissolved N2 molecules be accessible to the catalyst but block excess water, the designed N2 rich microenvironment over catalyst leads to an optimized Faradaic efficiency of 39.4% and an NH3 yield rate of 109.2 µg h−1 mg−1, which is superior to those of the most report metal‐based catalysts for electrochemical NRR. This study offers alternative strategy for enhancing NRR performance. [ABSTRACT FROM AUTHOR]

Microfluidic chips have emerged as significant tools in cell culture due to their capacity for supporting cells to adopt more physiologically relevant morphologies in 3D compared with traditional cell culture in 2D. Currently, irreversible bonding methods, where chips cannot be detached from their substrates without destroying the structure, are commonly used in fabrication, making it challenging to conduct further analysis on cells that have been cultured on-chip. Although some reversible bonding techniques have been developed, they are either restricted to certain materials such as glass, or require complex processing procedures. Here, we demonstrate a simple and reversible polydimethylsiloxane (PDMS)–polystyrene (PS) bonding technique that allows devices to withstand extended operations while pressurized, and supports long-term stable cell cultures. More importantly, it allows rapid and gentle live cell extraction for downstream manipulation and characterization after long-term on-chip culturing, and even further subculturing. Our new approach could greatly facilitate microfluidic chip-based cell and tissue cultures, overcoming current analytical limitations and opening up new avenues for downstream uses of on-chip cultures, including 3D-engineered tissue structures for biomedical applications. [ABSTRACT FROM AUTHOR]

Due to their eco‐friendly and functional attributes, the development of stain‐resistant poly(lactic acid) (PLA) fibers offers a multitude of benefits, including enhanced sustainability, ease of maintenance and expanded application fields. To investigate the feasibility of facile fabrication of stain‐resistant poly(lactic acid) (PLA) fibers, hydrophobic PLA fibers were produced using a scalable melt spinning technique employing silicone powder as the hydrophobic functional material. The influence of silicone powder content on the morphology and crystal structure of PLA fibers was investigated using different length scale characterization methods, including scanning electron microscopy and wide‐angle X‐ray diffraction. The relationships between the mechanical performance, hydrophobicity, and structure of the PLA fibers were established. The results showed that the synergistic effect of the micro/nanoconvex structure on the fiber surface created by silicon dioxide (SiO2) in silicone powder and the low surface energy of polydimethylsiloxane (PDMS) can considerably improve the hydrophobic functionality of the fibers. Compared with that of PLA fibers, the contact angle of hydrophobic PLA fibers increases from 67.3° to 87.6° with the addition of 3 wt% silicone powder. Furthermore, although silicone powder may accelerate PLA crystallization nucleation, it does not increase the crystallite size. When the silicone powder content is increased to 4 wt%, the mesophase fraction of the hydrophobic PLA fibers increases from 9.3% to 13.7%. This is the primary structural factor that allows the fiber to maintain its good tenacity. The tenacity of these hydrophobic PLA fibers is approximately 4.5 cN/dtex, which has excellent practical value. [ABSTRACT FROM AUTHOR]

Quantifying small amounts of the 17-hydroxyprogesterone in various matrix is crucial for different purposes. In this study, a commercial polydimethylsiloxane stir bar was used to extract hormone from water and urine samples. Analysis was performed by high-performance liquid chromatography using a UV detector. The response surface methodology was used to optimize the desorption and extraction steps, with predicted optimal point relative errors of 1.25% and 6.40%, respectively. The optimized method was validated with a linear range of 1.21–1000.00 for aqueous and 2.43–2000.00 ng mL–1 for urine samples. The coefficient of determination was 0.9998 and 0.9967, and the detection limit of the proposed method was obtained to be 0.40 and 0.80 ng mL–1 for aqueous and urine samples, respectively. The recovery percentage and relative standard deviation within a day and between three days after the addition of three different concentration levels of the standard to the control sample were 87–103% and 0.4–3.6% for aqueous and 87.5–101% and 0.1–5.2% for urine samples, respectively. The results show that the proposed method can be appropriate and cost-effective for extracting and analyzing this hormone. In addition, using three different tools, the greenness of the proposed method was proven. [ABSTRACT FROM AUTHOR]

Flexible strain sensors are widely used in the fields of human motion monitoring, electronic skin, and soft robotics. In this work, to satisfy the demand for high‐sensitivity, low‐cost, and fast‐response flexible strain sensors for these fields, embedded 3D printing (E‐3DP) technology is employed to fabricate highly sensitive and fast‐responding flexible strain sensors. The effects of conductive carbon paste concentration and printing process parameters by establishing the E‐3DP system on the piezoresistive behavior of the sensor were investigated. The results show that the gauge factor of the strain sensor is about 36.1 and 247.67, under the strain of 0%–40% and 40%–45%, respectively. Its response/recovery time is about 250/350 ms. On this basis, the sensor can also accurately sense and distinguish the motion in distinct parts of the human body, demonstrating that the flexible strain sensor manufactured by the method possesses the potential to be widely used in the fields of human motion monitoring, electronic skin, and soft robotics. [ABSTRACT FROM AUTHOR]

Despite plenty of static and dynamic mechanical measurements and modeling for bulk polydimethylsiloxane (PDMS) specimens, a notable gap exists in comprehensively understanding the dynamic mechanics under large cycle, low strain conditions, especially for microscale samples. This study integrates tensile testing and nanoindentation techniques to compare dynamic mechanical response for bulk PDMS samples and μ-pillars. The results from cyclic tensile testing, which involved up to 10,000 cycles at a strain range of 10%–20%, indicate a stabilization of energy dissipation rate after the initial 25 cycles. This attributes to stress relaxation and strain hardening, validating by rapid dual-phase exponential decay in maximum stress, coupled with an incremental increase in elastic modulus. In comparison to tensile testing, μ-pillars exhibited a 0.82% reduction in stiffness, stabilizing ~600th cycle. Concurrently, there was an approximately twofold increase in approaching distance during the initial 120 cycles, and an approximately fourfold increase in dissipated energy over the first 80 cycles, before reaching a plateau. This lagging hysteresis effect attributes to the distribution of the resultant force, including top tension, bottom compression, and base tilt. Overall, this study illuminates temporal mechanical deformations in PDMS under two application scenarios, enhancing our understanding of PDMS mechanical behavior. [ABSTRACT FROM AUTHOR]

Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer composites. In this work, graphite oxide (GO) and functionalized carbon nanotubes (f-CNTs) are combined to prepare "Line-Plane"-like hetero-structured thermally conductive GO@f-CNTs fillers, which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via self-sacrificing template method based on oxalic acid. Subsequently, thermally conductive GO@f-CNTs/polydimethylsiloxane (PDMS) composites are fabricated via casting method. When the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%, GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient (λ, 4.00 W·m−1·K−1), about 20 times that of the λ of neat PDMS (0.20 W·m−1·K−1), also much higher than the λ (2.44 W·m−1·K−1) of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed fillers. Meanwhile, the obtained GO@f-CNTs/PDMS composites have excellent thermal stability, whose λ deviation is only about 3% after 500 thermal cycles (20–200 °C). [ABSTRACT FROM AUTHOR]

One approach to address climate change is to replace vapor cooling systems with less harmful technologies. Solid-state refrigeration shows promise because it virtually eliminates the use of greenhouse gases. This paper proposes a concept for a barocaloric regenerator tube bank setup using a solid-state refrigerant, specifically encapsulated pure polydimethylsiloxane rubber. We presented the geometric requirements, operating parameters, and thermal performance of this setup. Given the complexity of simulating the full caloric process, we employed a simple two-dimensional finite element analysis to study the transient thermal and fluid phenomena. We discussed the temperature gradient of the active barocaloric matrix over time in the regenerator. For an isostatic pressure of 130 MPa, the best coefficient of performance for refrigeration achieved was 4.7 using a five-tube arrangement. [ABSTRACT FROM AUTHOR]

Laser micromachining has been used as an alternative to producing microfluidics structures and simplifying the conventional soft lithography process. In this paper we characterize the excimer laser micromachining parameters and demonstrate its application by producing several microfluidic structures in polydimethylsiloxane (PDMS). The parameters include the number of laser pulses, laser energy and rectangular variable aperture (RVA) in both x- and y-directions. We found that the laser energy and pulse rate affect the depth of micromachining d channels, while RVA in both x- and y-directions affects the width of the channels. Repetition of laser scan does not change the channel width but significantly changes the channel depth. Proper adjustment for laser energy and pulse rate is required to fabricate a desired channels depth. In order to demonstrate the microfabrication capability of an excimer laser with the optimal operating parameters, several microfluidic structures were micromachining d into PDMS with a KrF excimer laser. [ABSTRACT FROM AUTHOR]

We demonstrated the feasibility of obtaining a low-cost, flexible strain sensor by spraying a conductive thin layer of MWCNT's over an S-pattern embedded within a PDMS matrix. The final composite conforms a dog bone-shaped tensile specimen intended to measure the strain associated with a human wrist extension movement. Our sensor works with a combination of different mechanisms, such as piezoresistivity and tunneling, which depend on the level and repetitions of loads applied to the sensor. According to the reported elongation ratios, these sensors can detect large strains, up to 40%, for several uniaxial loading-unloading cycles. This makes them useful for human skin strain measurements. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane (PDMS) has been widely used to improve the antifouling properties of polyurethane (PU) coatings due to its low surface energy. Herein, a novel type of waterborne polyurethane (WPU) coating with good antifouling and self-healing abilities was synthesized by incorporating PDMS and disulfide bonds. The effects of PDMS and the disulfide content on the thermal, mechanical and surface properties of the coatings were investigated. Benefiting from a rational structural design, the obtained WPU coating manifested superior antifouling properties. In addition, the WPU coating exhibited good healing capabilities owing to the collaboration between dynamic disulfide bonds. Interestingly, the self-healing of an experimental crack occurred at a temperature above 60°C, and the coating recovered its mechanical properties to 95%. This finding has great significance for the design of multifunctional smart coatings for diverse applications. [ABSTRACT FROM AUTHOR]

Surfaces that combine low-toxicity antifouling effects with fouling-release properties are an intriguing possibility for developing effective measures against marine biofouling. This study field tested siloxane-based fouling-release surfaces enhanced by adding biodegradable surfactants. Two different surfactants were added to a standard polydimethylsiloxane (PDMS) surface, as well as to PDMS soaked in silicone oil, and compared to controls without surfactant augmentation. Antifouling and fouling-release performance was assessed over 11 to 13 weeks against the most prominent fouling species at three locations in Cape Breton, Nova Scotia, Canada. Using nonlinear mixed effect analysis, surfactants were found to have little impact on the progression of biofouling on PDMS without silicone oil in all three sites and had no additional impact on the progression of biofouling on PDMS augmented with silicone oil. (Silicone oil was found to delay biofouling in PDMS without other additives.) Given the known toxicity of some surfactants to invertebrate larvae, future efforts should consider either higher concentrations or alternative varieties for incorporation into fouling-release surfaces. [ABSTRACT FROM AUTHOR]

Thin coating layers of cross-linked polydimethylsiloxane (PDMS) and inorganic particles including glass spheres (GS), colloidal and fumed silica (aero and N20), montmorillonite (MMT), and kaolin (K) were attached onto Grade 1 Whatman filter paper (WFP) substrates using the spraycoating procedure to achieve superhydrophobic hybrid paper sheets. Coating formulations were varied in terms of their PDMS molecular masses and inorganic particles to prepare different samples. The effect of PDMS molecular weight and change in inorganic particle composition on the optical properties, surface roughness, barrier properties, surface chemistry, and topography was investigated. Hybrid paper sheets with ΔE00 values lower than 1 could be achieved, the surface roughness of which could be decreased by increasing the PDMS molecular weight in the coating formulation. Scanning electron microscopy studies revealed a homogeneous coating distribution, resulting in significant improvements in both the air and water barrier properties of the hybrid paper sheets. Spectroscopic investigations revealed the presence of interactions between the coating layer and the underlying paper substrate. Moreover, the distribution behavior of the inorganic particles on the spraycoated surfaces using the proposed method was also investigated using model compounds. [ABSTRACT FROM AUTHOR]

Aim of the study was to evaluate the effect of lithium- and melatonin-containing sorbent based on aluminum oxide and polydimethylsiloxane on changes in the number of platelets during hemosorption modeling and on the features of the hemostatic response during dosed contact of the sorbent with blood in an in vitro experiment. Material and methods. An analysis of the effect of the porous sorbent modified with melatonin (MT, 0.15 %) and lithium (0.5 %) based on aluminum oxide and polydimethylsiloxane (Al2O3@PDMS/MT-Li) was carried out in comparison with sorbent without modifiers (Al2O3@PDMS) and modified with MT (Al2O3@PDMS/MT) on a number of donor blood clotting parameters under in vitro hemosorption conditions. Studies of the hemostatic system included assessment of platelet count, chronometric parameters, fibrinogen concentration, antithrombin activity and plasminogen content. For integral assessment, calibrated thrombography and computer thromboelastometry were used. Results and discussion. Contact of all studied sorbents with blood causes a moderate decrease in the number of platelets (by 5.3–10.1 % from initial). Comparison sorbents reduce fibrinogen concentration by 7.1–7.7 %, Al2O3@PDMS/MT-Li – by 2.6 times, which is likely due to the methodology for determining this protein against the background of the independent anticoagulant activity of lithium ions. Al2O3@PDMS and Al2O3@PDMS/MT cause the development of a hypercoagulable shift, as evidenced by a shortening of kaolin time (by 27.5 and 22.1 %, respectively) and of activated partial thromboplastin time (APTT) by 7.1 % for both sorbents. At the same time, when lithium was included in the sorbent, not only did the hypercoagulation shift not occur, but blood clotting was also inhibited, as evidenced by an increase in kaolin time and APTT by 1.2 and 1.6 times, respectively, as well as in silicone time. Conclusions. Modifying sorbents with biologically active substances, lithium and MT, makes it possible to obtain an original hemosorbent with new properties. The presented results demonstrated the absence of a hypercoagulable shift in donor blood after contact with a lithium-, MTcontaining sorbent in vitro and indicate the potential for its using as a basis for the development of safe drugs.

Abstract Quantifying small amounts of the 17-hydroxyprogesterone in various matrix is crucial for different purposes. In this study, a commercial polydimethylsiloxane stir bar was used to extract hormone from water and urine samples. Analysis was performed by high-performance liquid chromatography using a UV detector. The response surface methodology was used to optimize the desorption and extraction steps, with predicted optimal point relative errors of 1.25% and 6.40%, respectively. The optimized method was validated with a linear range of 1.21–1000.00 for aqueous and 2.43–2000.00 ng mL–1 for urine samples. The coefficient of determination was 0.9998 and 0.9967, and the detection limit of the proposed method was obtained to be 0.40 and 0.80 ng mL–1 for aqueous and urine samples, respectively. The recovery percentage and relative standard deviation within a day and between three days after the addition of three different concentration levels of the standard to the control sample were 87–103% and 0.4–3.6% for aqueous and 87.5–101% and 0.1–5.2% for urine samples, respectively. The results show that the proposed method can be appropriate and cost-effective for extracting and analyzing this hormone. In addition, using three different tools, the greenness of the proposed method was proven.

The capture of moisture from the atmosphere through condensation has the potential to provide a sustainable source of water. Here, we investigate the condensation of humid air at low subcooling condition (11 °C), similar to conditions for natural dew capture, and explore how water contact angle and contact angle hysteresis affect the rates of water capture. We compare water collection on three families of surfaces: (i) hydrophilic (polyethylene oxide, MPEO) and hydrophobic (polydimethylsiloxane, PDMS) molecularly thin coatings grafted on smooth silicon wafers, which produce slippery covalently attached liquid surfaces (SCALSs), with low contact angle hysteresis (CAH = 6°); (ii) the same coatings grafted on rougher glass, with high CAH (20°–25°); (iii) hydrophilic polymer surfaces [poly(N-vinylpyrrolidone), PNVP] with high CAH (30°). Upon exposure to water, the MPEO SCALS swell, which likely further increases their droplet shedding ability. MPEO and PDMS coatings collect similar volume of water (around 5 l m−2 day−1), both when they are SCALS and non-slippery. Both MPEO and PDMS layers collect about 20% more water than PNVP surfaces. We present a basic model showing that, under low heat flux conditions, on all MPEO and PDMS layers, the droplets are so small (600–2000 µm) that there is no/low heat conduction resistance across the droplets, irrespective of the exact value of contact angle and CAH. As the time to first droplet departure is much faster on MPEO SCALS (28 min) than on PDMS SCALS (90 min), slippery hydrophilic surfaces are preferable in dew collection applications where the collection time frame is limited. [ABSTRACT FROM AUTHOR]

Recently, the application of superhydrophobic coatings on insulators has emerged as an effective strategy for mitigating risks and damages. In the current investigation, a superhydrophobic coating formulated with polyurethane (PU) prepolymer and polydimethylsiloxane (PDMS) has been developed, featuring a surface layer of SiO2 nanoparticles (NPs) modified with fluoroalkyl silane (FAS). The identification of peaks within the ranges of 567, 650, 747, and 898 cm− 1, corresponding to CF, CF₂, and CF₃ bonds, along with the reduction of the peak associated with the hydroxyl group around 3433 cm− 1, substantiates the interaction between FAS13 and SiO2 nanoparticles. The resultant coating exhibited a 39% increase in hydrophobicity compared to the coating without nanoparticles. The surface modification of nanoparticles resulted in an escalated degradation rate for the USMN sample, reaching a temperature range of 300 to 400°C. This phenomenon is attributed to the interaction between the hydroxyl groups on the nanoparticle's surface and the Si-O bonds present in the FAS13 composition, leading to increased thermal resistance of the nanoparticle. This study successfully produced a PDMS/PU coating utilizing modified SiO2 particles through a self-stratified approach. This coating acts as an adhesive layer for high-voltage insulation surfaces, effectively protecting against water intrusion and dust accumulation. [ABSTRACT FROM AUTHOR]

Conductive polymer composites require high conductive filler loadings to achieve relatively ideal electromagnetic interference (EMI) shielding performance, which brings problems such as heavy weight and poor processability and ultimately limits their application in the aerospace field. To solve the above problems and realize the preparation of excellent EMI shielding composites with low filler loadings, a bipolar pulsed electric field-induced graphene nanoplatelets (GNPs) alignment method is proposed in this paper to improve the electrical conductivity and EMI shielding performance. The orientation and alignment of GNPs in the matrix were characterized by x-ray diffraction and scanning electron microscopy, and the results showed that GNPs formed a conductive network. The electrical conductivity of the composite material in the X-band was measured, and the results showed that the bipolar pulsed electric field could significantly improve the electrical conductivity of the composite material; the improvement percentage reached 100%–300% under the five filler loadings. In addition, the EMI shielding effectiveness of the composite material in the X-band was tested. The results showed that the EMI shielding effectiveness of the composite material with a mass fraction of 14% increased from 16.48–15.86 dB to 21.37–20.99 dB with the action of the bipolar pulsed electric field, and the improvement percentage was 32%. This is the first study on improving the EMI shielding performance of composite materials by applying a bipolar pulsed electric field, and it provides an effective method to prepare EMI shielding composites with low filler loadings. [ABSTRACT FROM AUTHOR]

Abstract Alcohol consumption, a pervasive societal issue, poses considerable health risks and socioeconomic consequences. Alcohol-induced hepatic disorders, such as fatty liver disease, alcoholic hepatitis, chronic hepatitis, liver fibrosis, and cirrhosis, underscore the need for comprehensive research. Existing challenges in mimicking chronic alcohol exposure in cellular systems, attributed to ethanol evaporation, necessitate innovative approaches. In this study, we developed a simple, reusable, and controllable device for examining the physiological reactions of hepatocytes to long-term alcohol exposure. Our approach involved a novel device designed to continuously release ethanol into the culture medium, maintaining a consistent ethanol concentration over several days. We evaluated device performance by examining gene expression patterns and cytokine secretion alterations during long-term exposure to ethanol. These patterns were correlated with those observed in patients with alcoholic hepatitis. Our results suggest that our ethanol-releasing device can be used as a valuable tool to study the mechanisms of chronic alcohol-mediated hepatic diseases at the cellular level. Our device offers a practical solution for studying chronic alcohol exposure, providing a reliable platform for cellular research. This innovative tool holds promise for advancing our understanding of the molecular processes involved in chronic alcohol-mediated hepatic diseases. Future research avenues should explore broader applications and potential implications for predicting and treating alcohol-related illnesses.

This paper systematically investigates the effective parameter on the performance of polydimethylsiloxane/graphene (PDMS@Gr)-based triboelectric nanogenerators (TENGs) as well as their applications. PDMS@Gr films containing 0, 0.05, 0.5, 1, and 1.5 wt.% graphene are synthesized, and their surface characteristics, mechanical behavior, and electrical properties are characterized. Vertical contact-separation mode TENGs are fabricated, and their performance is evaluated. The results demonstrate that the surface roughness and surface charge density are the most critical parameters for the performance of PDMS@Gr-based TENGs compared to the electrical and mechanical properties of the friction layers. The PDMS@Gr-based TENG with 1 wt.% graphene shows the highest power output of 2.6 W/m2 at an optimized working condition (5 Hz and 15 N). It also exhibits stable power output until 15,000 working cycles and displays battery-free applications by powering a light-emitting diode (LED) array, a calculator, a digital watch, and a digital thermometer.

The correlations between the electrical behavior and microstructural properties of samples consisting of particle composites fabricated from SiC particles embedded in a silicone matrix, were investigated using X-ray computed tomography. In the voltage field range 200-1000 V/mm, the measured conductivity as a function of SiC volume fraction exhibits two distinct gaps. Upon further investigations, we attribute these observations to percolation thresholds at the microscale. The first gap, corresponding to interconnections between SiC particles that were originally disconnected, is more significant at higher voltage; while the second one, resulting from shortening conductivity pathways between the external surfaces of the samples with the increase of SiC volume fraction, seems more sensitive to lower voltages and is correlated with a decrease of the tortuosity of the percolated SiC network. [ABSTRACT FROM AUTHOR]