Self-healing Polymers Research Articles

Construction of self-healing multifunctional hyper-crosslinked hyperbranched polymer @ metal–organic polyhedra (HHMOP) membranes

The preparation of hybrid membranes composed of polymer matrix and porous materials is a hot topic. Herein, a highly reversible hyper-crosslinked hyperbranched polymer @ metal–organic polyhedra (HHMOP) membrane was designed and synthesized using hyperbranched polyamide amine (HPMA), UiO-66-NH2, diethylenetriamine, and terephthalaldehyde through a multi-component Schiff-base condensation reaction of aldehyde and amine groups. The structures of HHMOP membranes were characterized by FTIR, XRD, and SEM. The mechanical properties, thermal properties, reversible self-healing properties, and biological activity of the membranes were studied. Introducing HPMA as hyper-crosslinking monomer and UiO-66-NH2 as porous comonomers into the network resulted in HHMOPs membranes with multiple functionalities: flexibility, humidity sensitivity, self-healing capacity, antibacterial capacity and better mechanical properties than the original polyimine films. The tensional intensity and breaking elongation of HHMOP membrane has been remarkably ameliorated, with the maximum tensile strength reached 54.64 MPa. The membranes showed humidity-sensitive mechanical properties and excellent self-healing performance, with 91.35 % strength revovered after 24-hours at room temperature and a relative humidity of 60 %, indicating that HPMA has a significant impact on the humidity responsiveness and self-healing performance of HHMOP membranes. The HHMOP membrane also demonstrated good antibacterial activity against common food lethal bacteria like the gram-positive Staphylococcus aureus and gram-negative Escherichia coli. This work will greatly enrich the devise and preparation of versatile membranes and broaden the use of MOFs.

Current Trends and Perspectives of Polymers in Batteries.

This Perspective aims to present the current status and future opportunities for polymer science in battery technologies. Polymers play a crucial role in improving the performance of the ubiquitous lithium ion battery. But they will be even more important for the development of sustainable and versatile post-lithium battery technologies, in particular solid-state batteries. In this article, we identify the trends in the design and development of polymers for battery applications including binders for electrodes, porous separators, solid electrolytes, or redox-active electrode materials. These trends will be illustrated using a selection of recent polymer developments including new ionic polymers, biobased polymers, self-healing polymers, mixed-ionic electronic conducting polymers, inorganic-polymer composites, or redox polymers to give some examples. Finally, the future needs, opportunities, and directions of the field will be highlighted.

Self-healing and antistatic waterborne polyurethane hybrid coating resulting from hard but reversible Zr-O-Si networks

Robust, self-healing waterborne coatings have become the preferred choice in the field of flexible electronic devices owing to their outstanding compliance, restorability, and environmental friendliness. Nevertheless, most of the existing self-healing waterborne polymers exhibit viscoelasticity, irreversible fatigue damage, and the challenge of reconciling self-healing functions with mechanical properties, all stemming from inherent molecular structure contradictions between flexibility and rigidity. Here, we propose a novel strategy that utilizes a nanofiller with dynamic reversible bonds to overcome the self-healing limitations that theoretically demand flexible chain, for achieving both mechanical robustness and self-healing ability in the waterborne polyurethane (WPU) hybrid coating system. We modified tetrapropyl zirconate (TPOZ) with 3-aminopropyltriethoxysilane (APTES) to enhance compatibility between the matrix and inorganic particles, while the formation of dynamic reversible bonds through both condensation hydrolysis endows the self-healing abilities. The WPU hybrid coating was designed by covalently incorporating amino-modified TPOZ (A-ZrO2) into a glycinamide-functionalized WPU network, conferring excellent fracture energy (50.3 kJ/m2), elastic recovery, along with antistatic capability to the coating. Furthermore, the hybrid coating maintains a robust mechanical performance alongside 92.58 % of healing efficiency, exhibiting a potential for flexible electronics application. The hybridization strategy via incorporation of the nanofillers with hard but reversible covalent bond resolves the inherent robustness-healing trade-off, providing exciting thoughts to expand WPU applications.

Interfacial self-healing polymer electrolytes for Long-Cycle silicon anodes in High-Performance solid-state lithium batteries

For all-solid-state lithium-ion batteries (ASSLIBs), silicon (Si) stands out as an appealing anodes material due to its high energy density and improved safety compared to lithium metal. However, the substantial volume changes during cycling result in poor solid-state physical contact and electrolyte–electrode interface issues, leading to unsatisfactory electrochemical performance. In this study, we employed in-situ polymerization to construct an integrated Si anodes/self-healing polymer electrolyte for ASSLIBs. The polymer chain reorganization stems from numerous dynamic bonds in the constructed self-healing dynamic supermolecular elastomer electrolyte (SHDSE) molecular structure. Notably, SHDSE also serves as a Si anodes binder with enhanced adhesive capability. As a result, the well-structured Li|SHDSE|Si-SHDSE cell generates subtle electrolyte–electrode interface contacts at the molecular level, which can offer a continuous and stable Li+ transport pathway, reduce Si particle displacement, and mitigate electrode volume expansion. This further enhances cyclic stability (>500 cycles with 68.1 % capacity retention and >99.8 % Coulombic efficiency). More practically, the 2.0 Ah wave-shaped Si||LiCoO2 soft-pack battery with in-situ cured SHDSE exhibits strongly stabilized electrochemical performance (1.68 Ah after 700 cycles, 86.2 % capacity retention) in spite of a high operating temperatures up to 100 °C and in various bending tests. This represents a groundbreaking report in flexible solid-state soft-pack batteries containing Si anodes.

Recent Advances in Polymer Nanocomposites: Unveiling the Frontier of Shape Memory and Self-Healing Properties-A Comprehensive Review.

Shape memory and self-healing polymer nanocomposites have attracted considerable attention due to their modifiable properties and promising applications. The incorporation of nanomaterials (polypyrrole, carboxyl methyl cellulose, carbon nanotubes, titania nanotubes, graphene, graphene oxide, mesoporous silica) into these polymers has significantly enhanced their performance, opening up new avenues for diverse applications. The self-healing capability in polymer nanocomposites depends on several factors, including heat, quadruple hydrogen bonding, π-π stacking, Diels-Alder reactions, and metal-ligand coordination, which collectively govern the interactions within the composite materials. Among possible interactions, only quadruple hydrogen bonding between composite constituents has been shown to be effective in facilitating self-healing at approximately room temperature. Conversely, thermo-responsive self-healing and shape memory polymer nanocomposites require elevated temperatures to initiate the healing and recovery processes. Thermo-responsive (TRSMPs), light-actuated, magnetically actuated, and Electrically actuated Shape Memory Polymer Nanocomposite are discussed. This paper provides a comprehensive overview of the different types of interactions involved in SMP and SHP nanocomposites and examines their behavior at both room temperature and elevated temperature conditions, along with their biomedical applications. Among many applications of SMPs, special attention has been given to biomedical (drug delivery, orthodontics, tissue engineering, orthopedics, endovascular surgery), aerospace (hinges, space deployable structures, morphing aircrafts), textile (breathable fabrics, reinforced fabrics, self-healing electromagnetic interference shielding fabrics), sensor, electrical (triboelectric nanogenerators, information energy storage devices), electronic, paint and self-healing coating, and construction material (polymer cement composites) applications.

Delamination of Plasticized Devices in Dynamic Service Environments.

With the continuous development of advanced packaging technology in heterogeneous semiconductor integration, the delamination failure problem in a dynamic service environment has gradually become a key factor limiting the reliability of packaging devices. In this paper, the delamination failure mechanism of polymer-based packaging devices is clarified by summarizing the relevant literature and the latest research solutions are proposed. The results show that, at the microscopic scale, thermal stress and moisture damage are still the two main mechanisms of two-phase interface failure of encapsulation devices. Additionally, the application of emerging technologies such as RDL structure modification and self-healing polymers can significantly improve the thermal stress state of encapsulation devices and enhance their moisture resistance, which can improve the anti-delamination reliability of polymer-based encapsulation devices. In addition, this paper provides theoretical support for subsequent research and optimization of polymer-based packages by summarizing the microscopic failure mechanism of delamination at the two-phase interface and introducing the latest solutions.

Structural Design Strategy of a Biobased Allyl Compound with Dynamic Boronic Ester Bonds to Form Rigid-Soft Self-Healing Polymer Networks via Thiol–Ene “Click” Photopolymerization for Integrated Preparation of a Flexible Device

Structural Design Strategy of a Biobased Allyl Compound with Dynamic Boronic Ester Bonds to Form Rigid-Soft Self-Healing Polymer Networks via Thiol–Ene “Click” Photopolymerization for Integrated Preparation of a Flexible Device

Dynamic Interfaces in Self-Healable Polymers.

It is well-established that interfaces play critical roles in biological and synthetic processes. Aside from significant practical applications, the most accessible and measurable quantity is interfacial tension, which represents a measure of the energy required to create or rejoin two surfaces. Owing to the fact that interfacial processes are critical in polymeric materials, this review outlines recent advances in dynamic interfacial processes involving physics and chemistry targeting self-healing. Entropic interfacial energies stored during damage participate in the recovery, and self-healing depends upon copolymer composition and monomer sequence, monomer molar ratios, molecular weight, and polymer dispersity. These properties ultimately impact chain flexibility, shape-memory recovery, and interfacial interactions. Self-healing is a localized process with global implications on mechanical and other properties. Selected examples driven by interfacial flow and shape memory effects are discussed in the context of covalent and supramolecular rebonding targeting self-healable materials development.

Cellulose nanocrystals/fluorinated polyacrylate with mechanical tunability, water-oil resistance and self-healing capability via light actuated reversible associations

Traditional fluorinated polyacrylate has been extensively applied in various fields, which is favored by many researchers. However, the polymer usually can lose usefulness when it is damaged. Endowing the polymer with self-healing capability provides a potential solution to address the conflict. Herein, a series of photo actuated self-healing fluorinated polyacrylate based on coumarin groups was synthesized by reversible addition-fragmentation chain transfer (RAFT)-assisted Pickering emulsion polymerization using the modified cellulose nanocrystals as the stabilizer, n-butyl acrylate (BA) as the soft monomer, and methyl methacrylate (MMA) as the hard monomer. The influences of the dosage of 7-(4-vinylbenzyloxy)−4-methylcoumarin) (VBMC) and the mass ratio of BA to MMA on the emulsion polymerization and latex film properties were studied. The results showed that the latex particle size and its distribution decreased and then increased as the VBMC dosage and the mass ratio of BA to MMA increased. The latex film exhibited not only high ultimate tensile stress (6.36 MPa) and large stretchability (575.71%) but also a certain anti-fatigue characteristic. The water and oil contact angles of latex film could reach 118.5° and 101.7°, respectively. Besides, the latex film could achieve efficient self-healing capability due to the mobility of polymer chains associated with low glass transition temperature (Tg) and the reversible [2+2] cleavage/dimerization reaction of the coumarin groups upon ultraviolet (UV) irradiation of 254 nm and 365 nm. The work offers a substantial reference for developing different light actuated self-healing polymers with great prospects and promising futures.

Design of near-infrared responsive self-healing photocured polyurethane materials with thiourethane bonds

In this work, a photopolymerizable polyurethane oligomer (PETU) with thiourethane bonds was designed and synthesized. Afterwards, the near-infrared responsive self-healing polyurethane films (PETU-HI-X) were fabricated by photopolymerization using homemade PETU, polydopamine (PDA), and commercially available isobornyl acrylate (IBOA) and 2-hydroxyethyl acrylate (HEA). PETU-HI-X have good photopolymerization and photothermal conversion performance. The as-prepared near-infrared responsive self-healing polyurethane polymer PETU-HI-1.0 exhibited a tensile stress of 1.06 MPa, strain of 1021 %, initial decomposition temperature of 290 °C. In addition, the temperature of the material can rise to more than 100 °C after irradiation with near-infrared light for 3 min, showing excellent photothermal conversion performance, based on which the material shows more than 90 % self-healing efficiency after irradiation with near-infrared light for 30 min. More importantly, the near-infrared responsive self-healing polyurethane polymer PETU-HI-1.0 also has an excellent degradation property. The self-healing polyurethane films have also been used to prepare the flexible electronic device that can be healed and fully restored their conductivity after getting damaged.

NH2 functionalized MWCNT based self-healing conductive composite for smart sensing

Amino (NH2) functionalized multi-walled carbon nanotubes (MWCNTs) provide superior electrical and mechanical properties, comes at high material cost. The objective of this study is to develop a low-cost, simple, and effective method of NH2-MWCNTs synthesis. To this objective, we have developed in-house NH2 functionalized MWCNTs by reacting with NH4OH using hydrothermal synthesis process. The synthesized NH2-MWCNTs is compared and found compatible to the commercially available one, which is then used to develop self-healing and stretchable (SHS) conductive composite by incorporating into the self-healing supramolecular polymer. The electro-mechanical and self-healing properties of the composite can be tuned by controlling the amount of NH2-MWCNTs loading into the polymer matrix. The optimized composite showed a maximum strength of 286.15 kPa at its maximum strain rate of 410 %, and a high electrical conductivity of 8.23 S cm−1. It is further utilized to demonstrate SHS strain sensor for biomechanical signal detection, which exhibits high sensitivity to human wrist’s flexion and extension. Furthermore, it exhibits a high sensitivity with average TCR value of −5.2 % ℃-1 in a wider temperature range (25–100 ℃). Considering the low-cost in-house synthesis approach as well as the developed sensors’ performances, this study will put a paradigm shift within this research field.

Self-healing and shape-memory polymers based on cellulose acetate matrix

ABSTRACT The creation of self-healing polymers with superior strength and stretchability from biodegradable materials is attracting increasing attention. In this study, we synthesized new biomass-derived cellulose acetate (CA) derivatives by ring-opening graft polymerization of δ-valerolactone followed by the introduction of ureidopyrimidinone (Upy) groups in the polymer side chains. Due to the semicrystalline aliphatic characteristics of the side chain poly(δ-valerolactone) (PVL) and quadruple hydrogen bonds formed by the Upy groups, the stretchability of the resulting polymers was significantly enhanced. Moreover, the shape memory ability and self-healing property (58.3% of self-healing efficiency) were successfully imparted to the polymer. This study demonstrates the great significance of using biomass sources to create self-healing polymers.

Practical Applications of Self-Healing Polymers Beyond Mechanical and Electrical Recovery.

Self-healing polymeric materials, which can repair physical damage, offer promising prospects for protective applications across various industries. Although prolonged durability and resource conservation are key advantages, focusing solely on mechanical recovery may limit the market potential of these materials. The unique physical properties of self-healing polymers, such as interfacial reduction, seamless connection lines, temperature/pressure responses, and phase transitions, enable a multitude of innovative applications. In this perspective, the diverse applications of self-healing polymers beyond their traditional mechanical strength are emphasized and their potential in various sectors such as food packaging, damage-reporting, radiation shielding, acoustic conservation, biomedical monitoring, and tissue regeneration is explored. With regards to the commercialization challenges, including scalability, robustness, and performance degradation under extreme conditions, strategies to overcome these limitations and promote successful industrialization are discussed. Furthermore, the potential impacts of self-healing materials on future research directions, encompassing environmental sustainability, advanced computational techniques, integration with emerging technologies, and tailoring materials for specific applications are examined. This perspective aims to inspire interdisciplinary approaches and foster the adoption of self-healing materials in various real-life settings, ultimately contributing to the development of next-generation materials.

Investigating the Structure–Property−Processing Relationship of Polycaprolactone-Based 3D Printed Self-Healing Polymer Blends

Investigating the Structure–Property−Processing Relationship of Polycaprolactone-Based 3D Printed Self-Healing Polymer Blends

Silver Nanoparticle-Assisted Electrochemically Exfoliated Graphene Inks Coated on PVA-Based Self-Healing Polymer Composites for Soft Electronics.

Smart sensors with self-healing capabilities have recently aroused increasing interest in applications in soft electronics. However, challenges remain in balancing the sensors' self-healing and compatibility between their sensing and substrate layers. This study evaluated several self-healing polymer substrates and graphene ink-based strain-sensing coatings. The optimum electrochemically exfoliated graphene (e-graphene)/silver nanoparticle-coated tannic acid (TA)/superabsorbent polymer/graphene oxide (GO) blended poly(vinyl alcohol) polymer composites exhibited improvements of 47.1 and 39.2%, respectively, for the healing efficiency in a substrate crack area and in the graphene-based sensing layer due to conductive layer adhesion. While TA was found to improve healing efficiency on the coating surface by forming hydrogen bonds between the sensing and polymer layers, GO healed the polymer surface due to its ability to form bonds in the polymer matrix. The superabsorbent polymer was found to absorb excess water in e-graphene dispersion due to its host-guest interaction, while also reducing the coating thickness.

Structural and thermoanalytical characterization of self-healing polymer: the effect of cross-linking density

The effect of the gradually formed cross-linked structure on the thermal properties and swelling behaviour of modified poly(vinyl alcohol) was investigated. To this aim, the semi-crystalline polymer was functionalized with aldehyde and amino moieties to produce polymers with dynamic imine cross-links, and, thus, with self-healing or curing ability. With increasing degree of functionalization (0.89–7.12%), denser polymer networks cross-linked by dynamic imine bonds were formed, the samples systematically developed thermoset-like properties compared to the pristine, initially thermoplastic PVA. As a result, the introduction of new moieties into the initial PVA lowered the glass transition (from 65.3 to 35.0 °C) and melting temperatures (from 194 to 161 °C), however, a new peak (Tcrd) with growing enthalpy values appeared on the DSC curves, which indicates that more and more energy must be supplied in order to break the imine cross-links formed between the introduced aldehyde and amino groups. The significant impact of the degree of functionalization and cross-linking density on the polymer structure was also clearly demonstrated: the crystallinity decreased as the abundance of the introduced moieties increased and the formation of cross-links proceeded. At the same time, the water desorption enthalpies of the samples increased, suggesting a stronger, chemically cross-linked thermoset-like polymer network compared to the thermoplastic poly(vinyl alcohol).Graphical abstract

A biomass-rich, self-healable, and high-adhesive polymer binder for advanced lithium-sulfur batteries

Although lithium-sulfur (Li-S) batteries have attracted a great deal of attention due to their ultrahigh energy density, the significant dissolution and shuttle of polysulfides, coupled with the unstable electrode structure, result in a substantial decline in capacity, thereby hindering their practical application in rapidly advancing energy storage systems. In this work, we prepare an environmentally friendly binder (LA-GA) that possesses self-healing abilities and high adhesion by combining dynamic disulfide (SS) bonds with abundant polar functional groups. Significantly, the self-healing capability provided by SS bonds facilitates the repair of cracks resulting from cathode volume expansion. Simultaneously, the polar functional groups (carboxyl and pyrogallol) not only enhance adhesion, preserving cathode integrity, but also effectively participate in lithium polysulfide adsorption, thereby inhibiting the shuttle effect. As a result, sulfur cathodes incorporating the LA-GA binder demonstrate favorable cycling stability, with a high capacity retention of 81.9 % when tested at 0.2C for 100 cycles. Additionally, the long-term cycling performance is satisfactory, showing a small capacity decline rate of 0.0469 % per cycle over 700 cycles at 1.0C.

Self-healing polymer exhibits autonomous alignment

Self-healing polymer exhibits autonomous alignment

Synthesis of Tough and Fluorescent Self-Healing Elastomers by Scandium-Catalyzed Terpolymerization of Pyrenylethenylstyrene, Ethylene, and Anisylpropylene.

The synthesis of fluorescent self-healing polymers by the incorporation of a fluorophore-containing olefin into a polyolefin backbone through catalyst-controlled multicomponent copolymerization is of fundamental interest and practical importance, but such an approach has remained unexplored to date. Herein, we report for the first time the synthesis of tough and fluorescent self-healing polymers by sequence-controlled terpolymerization of 4-[2-(1-pyrenyl)ethenyl]styrene (Pyr), ethylene (E), and anisylpropylene (AP) using a sterically demanding half-sandwich scandium catalyst. The resulting terpolymers consisted of relatively long alternating E-alt-AP sequences, isolated Pyr units, and short E-E blocks, which exhibited excellent tensile strength, remarkable self-healability, and high fluorescence quantum yield. The excellent mechanical and self-healing properties could be attributed to the nanophase separation of the crystalline E-E segments and the hard Pyr aggregates from a flexible E-alt-AP segment matrix, in which the Pyr units not only served as an efficient fluorophore but also played an important role in forming nanodomains and enhancing the polymer mobility. Furthermore, the styrenyl C═C bond of the Pyr unit in the terpolymers could undergo [2 + 2] cycloaddition under photoirradiation, which thus enabled the fabrication of a self-healable fluorescent two-dimensional image on a terpolymer film through photolithography. This work offers an unprecedented efficient protocol for the synthesis of a brand-new family of fluorescent self-healing materials, showcasing the high potential of catalyst-controlled sequence-regular copolymerization of different olefins for the creation of novel functional polymers.

Bio-based conductive polyurethane composites derived from renewable castor oil with enhanced self-healing ability for flexible supercapacitors

To alleviate the pressure on the petrochemical industry and address environmental concerns, the utilization of polyurethane (PU) derived from castor oil (CO) (as an ester polyol replacement of petrochemical-based materials) has garnered significant attention in recent decades. Extending the service life of materials requires imparting self-healing properties to vegetable oil-based polymers, an aspect that has received limited attention in current studies. However, low self-healing efficiency still poses a significant challenge, and non-conductivity also remains an obstacle in current research, crucial for their application in electronic devices. In this work, we present the first series of electrically self-healing biopolymer composites constructed by incorporating carbon nanotube (CNT) networks into crosslinked castor oil-based polyurethane (BPU) through a simple curing process. These materials address the challenges mentioned above and exhibit improved mechanical, electrical, and self-healing capabilities compared to other bio-based self-healing materials. The resulting BPU/CNT composite demonstrated exceptional repeated self-healing capacity, restoring both mechanical properties and electrical performance even after experiencing severe mechanical damage. Notably, this composite served as a conductive substrate in flexible solid-state supercapacitor (FSSC) devices. Consequently, the FSSC derived from the composite conductive substrate achieved an impressive 92.4 % self-healing efficiency even after undergoing 7 cutting/healing cycles. The device remained virtually unchanged even after being bent at a 180° angle with a bending radius of 1.6 mm, indicating excellent repeatability and durability. The exceptional self-healing ability, with ∼98 % electrical recovery at 100 °C for 70 s and 93 % at 80 °C after 6 min, of these composites was attributed to the synergistic interactions of the dynamic exchange reactions of disulfide bonds and dense hydrogen bonds within the BPU matrix, which provide a reversible dynamic polymer network. The healing efficiency of these dynamic bonds was evaluated by adjusting the composition ratio of the long linear chain of pTHF in hybrid polyols of the crosslinked polymer network. Overall, this work highlights a series of green, simple, and highly efficient self-healing polymer composites derived from renewable castor oil, and it establishes an essential framework for future sustainable polymer composite design.