Strong Adhesion Strength Research Articles

Eutectogel adhesives with underwater-enhanced adhesion to hydrophilic surfaces and strong adhesion in harsh environments

It has been a challenge to achieve strong adhesion strength for gel adhesives in water. In this study, a novel eutectogel adhesive is synthesized via one-step photoinitiated polymerization of N-vinylpyrrolidone (NVP) in deep eutectic solvent (DES). The abundant hydrogen bonding interactions and the hydrophilic polyvinylpyrrolidone network structure endow the eutectogel with excellent adhesion to both hydrophilic and hydrophobic surfaces in air and underwater. Moreover, for hydrophilic substrates, the underwater adhesion strength of the eutectogel adhesives is 1.3 times larger than that in air, demonstrating an underwater-enhanced adhesion effect. In contrast, for hydrophobic substrates, the underwater adhesion strength is lower than in air. Furthermore, strong adhesion performance is maintained even in boiling water, strong acidic medium, strong basic medium, and organic solvents. The experimental and simulation results have unveiled the underwater adhesion enhancement mechanism of the eutectogel. It is believed that the designed eutectogel will show great promise in the development of the next-generation of gel adhesives with underwater adhesion capabilities and high environmental adaptability.

Polymeric silk fibroin hydrogel as a conductive and multifunctional adhesive for durable skin and epidermal electronics.

Silk fibroin (SF)-based hydrogels are promising multifunctional adhesive candidates for real-world applications in tissue engineering, implantable bioelectronics, artificial muscles, and artificial skin. However, developing conductive SF-based hydrogels that are suitable for the micro-physiological environment and maintain their physical and chemical properties over long periods of use remains challenging. Herein, we developed an ion-conductive SF hydrogel composed of glycidyl methacrylate silk fibroin (SilMA) and bioionic liquid choline acylate (ChoA) polymer chains, together with the modification of acrylated thymine (ThyA) and adenine (AdeA) functional groups. The resulting polymeric ion-conductive SF composite hydrogel demonstrated high bioactivity, strong adhesion strength, good mechanical compliance, and stretchability. The formed hydrogel network of ChoA chains can coordinate with the ionic strength in the micro-physiological environment while maintaining the adaptive coefficient of expansion and stable mechanical properties. These features help to form a stable ion-conducting channel for the hydrogel. Additionally, the hydrogel network modified with AdeA and ThyA, can provide a strong adhesion to the surface of a variety of substrates, including wet tissue through abundant hydrogen bonding. The biocompatible and ionic conductive SF composite hydrogels can be easily prepared and incorporated into flexible skin or epidermal sensing devices. Therefore, our polymeric SF-based hydrogel has great potential and wide application to be an important component of many flexible electronic devices for personalized healthcare.

Rapid Forming, Robust Adhesive Fungal-Sourced Chitosan Hydrogels Loaded with Deferoxamine for Sutureless Short-Gap Peripheral Nerve Repair.

Clinically, conventional sutures for repair of short-distance nerve injuries (< 5mm) may contribute to uncontrolled inflammation and scar formation, thus negatively impacting nerve regeneration. To repair transected peripheral nerves with short distances, a rapid-forming, robust adhesive chitosan hydrogel is prepared by synthesizing maleic and dopamine bi-functionalized fungal-sourced chitosan (DM) and subsequently photopolymerizing DM precursor solution. The hydrogel rapidly polymerized under UV light irradiation (≈2 s) and possessed a strong adhesive strength (273.33 ± 55.07kPa), facilitating a fast bonding of nerve stump. Especially, its tailored degradation profile over 28 days supported both early gap bridging and subsequent nerve regeneration. Furthermore, deferoxamine (DFO), a pro-angiogenic drug, is loaded into the hydrogel to reach sustainable release, accelerating axonal growth synergistically. A 3mm long sciatic nerve defects model in rats is used to investigate the efficacy of DM@DFO hydrogel for repairing peripheral nerve defects. After 60 days, the DM@DFO hydrogel significantly outperformed conventional sutures and fibrin glue, improving motor and sensory recovery by reducing inflammation, inhibiting scar formation, and accelerating vascular regeneration within 14 days post-repair. This work highlights the DM@DFO hydrogel as a promising tissue adhesive for effective short-distance peripheral nerve repair.

Effects of CrC interlayer on tribocorrosion properties of DLC-coated TC4 alloy in a 0.9 wt% NaCl solution

In this study, DLC coatings with varying thicknesses of CrC interlayers were fabricated on the surface of TC4 alloy by regulating the flow rate of C2H2. The effects of the interlayer layer on the microstructure, mechanical properties, corrosion resistance, and tribocorrosion resistance of DLC coatings were systematically investigated. The results show that as the C2H2 flow rate increases, the CrC interlayer exhibits the structure transitions from columnar crystals to amorphous, resulting in improved hardness. The hardness of the CrC40 interlayer reaches 17.2 GPa, significantly higher than the 9.3 GPa of the Cr underlayer. The CrC interlayer notably enhances the mechanical properties and adhesion strength of DLC coatings. The corrosion current density of the CrC40/DLC coating is 3.07 × 10−8 A/cm2, significantly lower than that of the DLC coating with only a Cr underlayer. Under high load conditions of 20 N, the tribocorrosion rate of the CrC40/DLC coating is reduced to 2.09 × 10−7 mm3.(N.m)−1, representing a significant decrease of 93.9 % compared to the DLC coating. The CrC40/DLC coating exhibits strong adhesion strength, appropriate internal stress and a relatively hard CrC40 interlayer, showing exceptional tribocorrosion resistance.

Direct Ink Writing of Highly Conductive and Strongly Adhesive PEDOT:PSS-EP Coatings for Antistatic Applications

As the information age progresses, the electronics industry is evolving towards smaller and more sophisticated products. However, electrostatic potentials easily penetrate these components, causing damage. This underscores the urgent need for materials with superior antistatic properties to safeguard electronic devices from such damage. Antistatic coatings typically rely on polymers as the primary material, enhanced with conductive fillers and additives to improve performance. Despite significant progress, these coatings still face challenges related to advanced processing technologies and the integration of electrical and mechanical properties. Among various conductive fillers, the conducting polymer PEDOT:PSS stands out for its exceptional conductivity, environmental stability, and long cycle life. Additionally, epoxy resin (EP) is widely utilized in polymer coatings due to its strong adhesion to diverse substrates during curing. Here, we develop highly conductive and strongly adhesive PEDOT:PSS inks by combining PEDOT:PSS with EP using a composite engineering approach. These inks are used to fabricate PEDOT:PSS coatings by direct ink writing (DIW). We systematically evaluate the DIW of PEDOT:PSS-EP coatings, which show high electrical conductivity (ranging from 0.59 ± 0.07 to 41.50 ± 3.26 S cm−1), strong adhesion (ranging from 15.84 ± 2.18 to 99.3 ± 9.06 kPa), and robust mechanical strength (8 MPa). Additionally, we examine the surface morphology, wettability, and hardness of the coatings with varying PEDOT:PSS content. The resultant coatings demonstrate significant potential for applications in antistatic protection, electromagnetic shielding, and other flexible electronic technologies.

Strong adhesive, high conductive and environmentally stable eutectogel based on “Water in deep eutectic Solvent”: Ultrasensitive flexible temperature and strain sensors

Eutectogel is a promising candidate of conductive materials for flexible electronic sensors. However, the existing eutectogel sensors still have some problems such as poor mechanical properties and antifatigue ability, limited ionic conductivity, and strong hygroscopicity. Herein, an eutectogel is fabricated via one-stop photoinitiated copolymerization of acrylic acid, hydroxyethyl acrylate, and highly branched modified polyethyleneimine in “water in deep eutectic solvent”. The optimized eutectogel exhibits strong adhesive strength (132 ± 9 kPa, with porcine skin), ultra elongation (3500 %), high conductivity (2.7 ± 0.1 mS cm−1), long term antidrying and antifreezing (∼30 d) in a wide range of working temperatures (−40 − 60 °C), flame resistance, biocompatability, and excellent resistance ability to tear and crack propagation. The superb flame resistance and sensitive response to temperature offer a potential application in fire alarm. Besides, this gel-based wearable strain sensors can sensitively monitor and differentiate large body joint movements and subtle muscle motions. The highly distinguishable and reproducible signals can be recorded while further utilizes as sensors for detecting human healthcare accurately and continuously in medical mobile electrocardiogram machine for a long time. This work provides a new strategy for constructing eutectogel based wearable devices and electronic devices with excellent performance.

Fully Physically Crosslinked PNIPAM Ionogels with High Mechanical Properties and Temperature‐Managed Adhesion Achieved by H2O/Ionic Liquid Binary Solvents

AbstractPoly(N‐isopropylacrylamide) (PNIPAM) gels change their volume and hydrophilicity in response to temperature stimulus in flexible actuators, flexible sensors, and energy storage management. However, traditional PNIPAM gels exhibit low mechanical properties and poor self‐recovery ability due to weak intermolecular (chain) interactions and necessary covalent crosslinking. Herein, a water/ionic liquid (H2O/IL) binary solvent system that provides additional hydrogen bonding and hydrophobic interactions as well as can significantly increase the solubility (up to 60 wt.%) of NIPAM is developed. The fully physically crosslinked PNIPAM ionogel is prepared by utilizing the H2O/IL binary solvent and exhibited excellent mechanical performances, rapid self‐recovery properties, and strong adhesion strength. In addition, the lower critical solution temperature of the PNIPAM ionogel can also be tuned over a wide range (37‐70 °C) by adjusting the IL ratio in the binary solvent. Furthermore, based on the temperature sensitivity and ionic conductivity of the PNIPAM ionogel, applications of PNIPAM ionogels in smart devices, temperature‐managed adhesion, and flexible sensing are demonstrated, respectively. This work improves various performances of PNIPAM gels by using the H2O/IL binary solvent to adjust non‐covalent interactions and provided new ideas for developing high‐performance temperature‐sensitive gels.

A Poly(Ionic Liquid)‐Based Polymer Binder for Endurable Lithium–Sulfur Batteries

AbstractThough polyvinylidene fluoride (PVDF) is widely‐used binder for conventional lithium‐sulfur (Li–S) batteries, it still encounters challenges of severe electrode fracture involved by drastic volume change upon repeating cycling, and lack of extended‐functions like trapping dissolved polysulfides and smoothing Li+ transfer. Herein, a methodology of grafting sulfophilic hydrogen‐bond donor and lithiophilic hydrogen‐bond acceptor to the polymer binder (named as PIL), function as gear teethes and tooth spaces, is reported. When cracks occur, the engaged gears driven by dynamic hydrogen bonds are separated, which are spontaneously reformed owing to the automatic meshing of gears, and thus accelerate the healing of cracks. At the molecular level, the synergetic effect of sulfophilic hydrogen‐bond donor and lithiophilic hydrogen‐bond acceptor enables polysulfides immobilization through “push‐pull effect”, facilitating the subsequent redox kinetics. Accordingly, the cross‐link network of hydrogen bonds endows the elaborated designed polymer binder with strong adhesive strength and rapid Li+ migration. Attributed to these beneficial properties, the PIL‐based sulfur cathode exhibits excellent rate performance and superior cycling durability (an ultralow capacity fading rate of 0.062% per cycle over 800 cycles at 2 C). Even with high sulfur loading of 9.27 mg cm−2, a high areal capacity of 8.71 mAh cm−2 can be achieved, verifying its potential application.

A Novel Approach towards the Preparation of Silk-Fibroin-Modified Polyethylene Terephthalate with High Hydrophilicity and Stability

Silk fibroin (SF) has been widely used in biomedical applications for the hydrophilicity modification of high molecular polymer materials. However, the challenge remains to immobilize SF with high structure stability and strong adhesion strength between SF and the substrate. Here, we propose an effective two-step process for modifying polyethylene terephthalate (PET) with SF: dipping PET film in SF solution and subsequently carrying out plasma-assisted deposition in SF aerosol. The structure and property analysis revealed that the SF-modified PET (PET-SF) prepared using the two-step method exhibited superior structural stability and stronger adhesion strength compared to the dip-coating method and the plasma-assisted deposition method. In addition, PET-SF prepared using the two-step method resulted in a higher concentration of SF and an increased content of active groups on its surface, enhancing its hydrophilicity compared to the other two methods. Additionally, the influence of dipping time and deposition time in the two-step method was investigated. The results demonstrated that the dipping time for 6 h and the deposition time for 3 min resulted in maximum SF grafting amount with a highly stable structure. Furthermore, the PET-SF exhibited satisfactory hydrophilicity when the deposition time was more than 3 min and showed the most hydrophilicity surface at 8 min.

In-situ fabrication of tungsten oxide film pH micro-sensor and its application on the pH monitoring of Fe-Cu galvanic corrosion

Localized and interface pH values are important parameters for studying the corrosion progress and complex interface reactions. Although commercial glass pH sensors have been widely used to measure solution pH value due to their advantages of long stability and high sensitivity, they were unable to determine the interface and microregion pH value for their difficulty in miniaturization. In this work, an all-solid-state pH micro-sensor with strong adhesion strength was in-situ fabricated on diameter 15 μm tungsten ultramicroelectrode (UME) using constant current anodizing. The pH micro-sensor showed good linear response (R2 = 0.999), excellent sensitivity (with a slope of −53.8 mV/pH), quick response (<0.1 s), long lifetime (>44 days) and great anti-interference ability to most of the ions in marine (selectivity coefficients pKij > 7), such as SO42−, Cl−, NO3−, K+, Mg2+ and Fe2+. Then, the pH micro-sensor, combined with the potentiometric mode of SECM, was further employed to explore the localized pH value distribution during the galvanic corrosion of Fe-Cu couple in 0.1 M NaCl solution. To further verify the anti-interference ability of pH micro-sensor, potentiometric SECM experiment was also conducted in artificial seawater. Results showed that both acidic sites and alkalizing sites appeared on the Fe surface, while homogeneous alkalization took place overall Cu surface. This was consistent with the SVET results that anodic and cathodic areas existed simultaneously on Fe surface. Thus, it could be concluded that local corrosion occurred on Fe surface and only part of the Fe surface acted as the anodic even under galvanic effect. However, Cu acted as cathode with the homogeneously distributing cathodic current on the whole surface during the galvanic corrosion.

Pd nanocubes enclosed by {100} facets for activating electroless Cu deposition on liquid crystal polymer substrates with strong adhesion strength

In this study, we investigate the catalytic performance of palladium (Pd) nanocatalysts with different surface atomic structures for activating electroless copper (Cu) deposition on liquid crystal polymer (LCP) substrates. These nanocatalysts include Pd nanocubes featuring {100} facets of square atomic arrangement as their predominant surface structure and Pd spherical nanoparticles characterized by random atomic arrangements, synthesized using an aqueous method. Our electrochemical measurements reveal that the induction time for the growth of Cu films is significantly shorter when utilizing Pd nanocubes compared to Pd nanospheres. This shorter induction time signifies a quicker initiation of Cu growth, primarily due to the presence of Pd {100} facets. Furthermore, we also develop a surface modification approach involving a crosslinking reaction that utilizes the highly branched polyethylenimine and linear polyvinylpyrrolidone on the Pd nanocubes. This method not only facilitates the adsorption of Pd nanocubes onto the LCP substrates but also achieves a robust peel adhesion strength (630 gf/cm) of the resulting Cu films, exceeding the industrial adhesion goal of 500 gf/cm. Moreover, in-depth synchrotron X-ray photoelectron spectroscopy analysis provides valuable insights into the depth-dependent chemical changes within the Cu films and proves the removal of Cu oxides after the acid treatment.

Superior tribological and sealing performance of micro-crystalline diamond coated silicon carbide seals under dry friction and high load

Silicon carbide seals suffer severe wear under the conditions of dry friction and high load, posing a great challenge in achieving a stable performance and a long lifetime. In this work, micro-crystalline diamond coatings were deposited on silicon carbide sealing rings to prevent the failure caused by wear. The deposited micro-crystalline diamond coatings exhibit high-quality crystallinity and strong adhesive strength with the silicon carbide substrate. In sealing tests, the micro-crystalline diamond coated silicon carbide sealing pair demonstrates superior tribological and sealing properties under dry friction and high load of 1800 N, featuring a low coefficient of friction of 0.16, a low wear rate of 4.00 × 10−7 mm3·N−1·m−1 and a high friction limit of 5.24 MPa·m·s−1. Characterizations of morphology, chemical composition and microstructure confirm that the smoothening effect on the contact face and the formation of graphite during the sealing test synergistically contribute to the outstanding tribological and sealing performance.

Effect of Spheroidizing Annealing Process on Microstructure and Properties of Quenching and Tempering 60Cr16MoMA Martensitic Stainless Steel

The effect of spheroidizing annealing on carbide characteristic parameters, mechanical properties and wear resistance of the quenching and tempering (Q&amp;T) high carbon martensitic stainless steel is investigated. The microstructure of the steel is characterized and analyzed through various techniques, including scanning electron microscope (SEM), X‐ray diffraction (XRD), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM). Results show that the microstructure of the annealing steel is mainly composed of ferrite and M23C6 carbide. With the rise of austenitizing temperature, the average diameter of carbide of the annealed steel increases. The average diameter of carbides in the Q&amp;T steel changes in the same way as that observed in the annealed steel. The steel has the lowest annealing hardness, highest Q&amp;T toughness, and wear resistance at an annealed soaking temperature of 860 °C. The influence factor of the toughness and wear resistance can be identified that small‐sized carbides and low angle grain boundaries exhibit strong interface adhesive strength. This reduces the probability of cracking in the particle or at the interface.

Strong-adhesion and nonfouling self-generating zwitterionic Janus hydrogel paint

Zwitterionic hydrogel paints are promising and ecofriendly materials to prevent biofouling and oil contamination. However, the weak adhesion of hydrogel paints to substrates and tedious fabrication and coating processes limit their practical applications. Herein, a novel self-generating zwitterionic Janus hydrogel paint consisting of a polymer copolymerized by methyl methacrylate (MMA), tertiary carboxybetaine triisopropylsilyl ester ethyl acrylate (TCBSi), and 3-(methacryloxypropyl) trimethoxysilane (KH570) is reported. The polymer, when coated on a substrate, self-crosslinks into the polymer network and interlinks to the substrate during curing. This polymer decouples polymerization from the crosslinking and interlinking processes. When used underwater, the top layer of the coating rapidly hydrolyzes and self-generates a zwitterionic hydrogel layer, whereas the hydrophobic bottom layer remains unhydrolyzed. Adhesion tests show that this coating has considerably stronger adhesion strength than traditional zwitterionic hydrogel coatings due to the synergistic effect of hydrophobic interactions and interface bonding. Moreover, it has excellent resistance to protein, bacteria (Escherichia coli, Staphylococcus aureus, and Pseudomonas sp.), and diatom (Navicula incerta). The self-generating zwitterionic Janus hydrogel coating can also prevent oil contamination. This study serves as a promising avenue for the design and fabrication as well as practical application of self-generating zwitterionic Janus hydrogel paint with strong substrate adhesion.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery.

Aqueous zinc-ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+-based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen-rich groups (conjugated cyclic -C=N-), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long-term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half-cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery

AbstractAqueous zinc‐ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+‐based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen‐rich groups (conjugated cyclic −C=N−), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long‐term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half‐cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

Enhanced Strength for Double Network Hydrogel Adhesive Through Cohesion‐Adhesion Balance

AbstractHydrogel adhesives exhibit great potential in various biomedical fields such as tissue sealing and soft robotics. However, the high‐water content and defective network structures of these hydrogel adhesives result in low intrinsic mechanical strength, severely impeding their application. In this study, it is reported that the strong hydrogel adhesive strength can be achieved when a balance is established between adhesive forces and cohesive forces. Based on this principle, a new double network (DN) design is created to combine an adhesive polyvinyl alcohol (PVA) as the first network with a flexible sodium alginate (SA) as the second network. A delicate balance is achieved between cohesion and adhesion by adjusting the ratio between the first rigid adhesive network and the second flexible network. As a result, this balanced DN hydrogel adhesive exhibits a strong tissue adhesion strength, approximately three times higher than that in the non‐balance situation.

Switchable Adhesive Based on Shape Memory Polymer with Micropillars of Different Heights for Laser-Driven Noncontact Transfer Printing.

Switchable adhesive is essential to develop transfer printing, which is an advanced heterogeneous material integration technique for developing electronic systems. Designing a switchable adhesive with strong adhesion strength that can also be easily eliminated to enable noncontact transfer printing still remains a challenge. Here, we report a simple yet robust design of switchable adhesive based on a thermally responsive shape memory polymer with micropillars of different heights. The adhesive takes advantage of the shape-fixing property of shape memory polymer to provide strong adhesion for a reliable pick-up and the various levels of shape recovery of micropillars under laser heating to eliminate the adhesion for robust printing in a noncontact way. Systematic experimental and numerical studies reveal the adhesion switch mechanism and provide insights into the design of switchable adhesives. This switchable adhesive design provides a good solution to develop laser-driven noncontact transfer printing with the capability of eliminating the influence of receivers on the performance of transfer printing. Demonstrations of transfer printing of silicon wafers, microscale Si platelets, and micro light emitting diode (μ-LED) chips onto various challenging nonadhesive receivers (e.g., sandpaper, stainless steel bead, leaf, or glass) to form desired two-dimensional or three-dimensional layouts illustrate its great potential in deterministic assembly.

Multifunctional radical polymers-enabled rapid charge/discharge and high capacity for flexible self-standing LiFePO4/PETM/SWNT hybrid electrodes

The combination of high output and high energy storage performance at the same time is a long-standing and formidable challenge in electrode technology. Herein, a multifunctional radical polymer binder, poly (ethylene-alt-TEMPO maleate) (PETM) is first introduced to construct flexible self-standing organic/inorganic hybrid electrodes, PETM/lithium iron phosphate (LFP)/single-walled carbon nanotubes (SWNT). Notably, PETM plays multifunctional roles in the PETM/LFP/SWNT electrodes as a polymer binder, electrochemical mediator, and auxiliary active material. First, PETM provides strong adhesive strength to generate robust structural integrity, allowing a three-dimensional hierarchical consecutive structure. Second, together with the electrochemical mediation of PETM, the hybrid structure greatly expedites electron/ion transportation, thus bringing fast redox reaction kinetics and high output. Third, PETM offer additional energy storage owing to the electro-activeness of radical groups. Coupled with the self-supporting property of the electrode without any redundant electro-inactive components, the electrode energy density can be substantially improved. Profiting from those advantages, the formed electrode achieves exceptional rate performance (97.5 mA h/g at 20 C), extraordinary specific/areal capacity (173 mA h g−1/8.2 mA h cm−2 at 0.1 C), and ultralong-life cycle under ultrahigh rate (over 2000 cycles at 20 C). More importantly, the electrode can be utilized as a flexible cathode in flexible batteries.

Multifunctional Acrylic Polymers with Enhanced Adhesive Property Serving as Excellent Edge Encapsulant for Stable Optoelectronic Devices.

Pendant groups in acrylic adhesive polymers (Ads) have a profound influence on adhesive and cohesive properties and additionally on encapsulant application. However, a systematic investigation to assess the impact of the pendant groups' length and bulkiness is rare, and there is not even a single report on applying Ads as interfacial adhesion promotors and encapsulation materials simultaneously. Herein, we have developed a series of multifunctional methacrylic polymers, namely, R-co-Ads, with varying pendant length and bulkiness (R = methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5), hexyl (C6), isobutyl (iC4), and 2-ethylhexyl (2EH)). The adhesion-related experimental results reveal that R-co-Ads have high transparency, strong adhesion strength to the various contact surfaces, and a fast cure speed. In particular, C1-co-Ad shows a superior adhesion performance with an improved cross-cut index of 4B and a shear bonding strength of 1.56 MPa. We also have adopted C1-co-Ad for encapsulation of various emerging optoelectronic applications (e.g., perovskite solar cell-, charge transport-, and conductivity-related characteristics), demonstrating its excellent edge encapsulant served to improve the device stability against ambient air conditions. Our study establishes the structure-adhesion-surface relationships, advancing the better design of adhesives and encapsulants for various research fields.