Jingxin Lei

As metal-containing resists attract increasing research interest in high-resolution lithography, gaining insights into the photochemical mechanisms, particularly in relation to the ligand functionality, is actively demanded. In this work, a controlled pair of organotin carboxylates with analogous structures but different functional groups has been designed and synthesized as deep-ultraviolet (DUV) resists. Both resists demonstrate 90 nm half-pitch resolution and the capability of pattern transfer on carbon-based hard-mask layers. Through various characterizations and comparison of the controlled pair, we propose two competitive reaction paths for the organotin system with olefin groups, which regulate the lithographic sensitivity and dissolution contrast. Our findings highlight the structural adjustability of organotin carboxylates and their potential application as high-resolution and etch-durable DUV resists.

Conventional materials typically maintain a stable solid state under specific application conditions. However, materials that combine high mechanical strength with reversible switching states are highly desirable for advanced technologies. Here, we present hydrogen-bond nanoconfined self-destructive polymers (HNSPs) that have robust mechanics and reversible solid-fluid switching capability at 25 °C. Upon exposure to moisture, HNSPs spontaneously transition from solid to fluid, with humidity-tunable switching rates. HNSPs with weight ratios (Rm) of 1.7 is 1.69 times higher self-destructive rate than those with Rm of 2.1, and at 90% relative humidity (RH), Rm=2.0 samples exhibit an 804.27% higher self-destructive efficiency than at 60% RH. Heating can reverse the fluid back to a solid, enabling reversible, humidity-programmable behavior. Mechanistically, large ordered hydrogen-bond clusters, reduced chain entanglement, and abundant hydrophilic groups collectively facilitate switching. This work provides a simple yet versatile strategy for designing robust, switchable self-destructive polymers, broadening their potential in next-generation devices.

The rapid advancement of smart, flexible electronic devices has paralleled a surge in electronic waste (e‐waste), exacerbating massive resource depletion and serious environmental pollution. Recyclable materials are extensively investigated to address these challenges. Herein, this study designs a unique polyurethane (SPPUs) with ultra‐high strength up to 60 MPa and toughness of 360 MJ m⁻³. This synthetic SPPUs can be fully recycled at room temperature by using green solvents of ethanol. Accordingly, the resultant SPPU‐Ni composites, created by mixing the ethanol‐dissolved SPPUs solution with nickel (Ni) powder, effectively combine the flexibility and recyclability of SPPUs with the electrical conductivity of the nickel filler. Notably, this work develops the printable capacitive sensors (PCBS) through transcribing the paste of SPPUs‐Ni slurry onto PET film and paper using screen‐printing technology. The devised PCBS have fast response time ≈50 ms, high resolution, and multiple signal recognition capabilities. Remarkably, SPPUs and Ni powder can be fully recycled by only dissolving the waste PCBS in ethanol. This work offers a sustainable solution to the growing e‐waste problem in recyclable flexible electronics.

A PEG-based FSPCM was prepared in water via a simple method, using mannitol as supporting material through intermolecular hydrogen bonding. This FSPCM has high latent heat values and can be chemically recycled with recycling rates over 90%.

It is a challenge to develop adhesives simultaneously capable of strong adhesion and efficient switchable ability. Herein, the authors report multifunctional switchable adhesives named Cu²⁺‐curcumin‐imidazole‐polyurethane (CIPUs:Cu²⁺) by introducing 1‐(3‐aminopropyl) imidazole and curcumin into polyurethane system crossed by Cu²⁺ forming dynamic metal‐ligand bonds. This CIPUs:Cu²⁺ has strong adhesion (up to 2.46 MPa) on various material surfaces due to their specially designed functional groups alike the secretions from mussels. It can achieve fast switching speed (30 s) and high switch efficiency through multiple contactless remote stimulations. Importantly, density functional theory (DFT) calculation reveals that such metal‐ligand bonds consisting of two components: stronger Cu²⁺‐curcumin complexes and weaker Cu²⁺‐imidazole complexes can aggregate to form multi‐level dynamic stable structure . The special structure can not only be acted as sacrificial sites for easily broken and reformed, allowing efficient switchable adhesion and enormous energy dissipation but also acted as firm sites to maintain the cohesion of the adhesive and the reversible reconstruction network. Intriguingly, the CIPUs:Cu²⁺ can achieve self‐healing at room temperature without needing external stimuli. Overall, this strategy can further broaden the design of switchable adhesives in the fields of intelligent gadgets, wearable bio‐monitoring devices, etc.

Epoxy resins are currently the most widely used thermosetting polymers due to their high thermal stability, excellent electrical insulation, and chemical resistance. However, the application of epoxy resins are greatly limited by their inherent defects of poor toughness, difficult recyclability, and lacking shape plasticity due to forming a three-dimensional network structure. In this work, a uniquely intrinsic toughened thermosetting epoxy resin, namely EPU, was synthesized via integrating a conductive black (CB) and polyurethane system into the traditional thermosetting epoxy resins. This work cleverly introduces polyurethane system into the molecular chain of an epoxy resin, not only improving its intrinsic toughness from the molecular structure level, but also endowing the epoxy resin with dynamic performance because of the reversible exchange reaction between carbamate bonds at high temperature. The devised EPU demonstrated tunable and remarkable mechanical properties by utilizing different ratios of polyurethane in the system, with the maximum value of ultimate tensile strength and elongation at break reaching 20.7 MPa and 430.1%. In particular, with the help of the dynamic performance, the synthetic conductive thermosetting epoxy resin (named here as EPU1-CBs) could realize the thermotropic shape memory function, displaying intriguing thermal- and electric-induced shape plasticity. In this dual-driven process, the voltage could be applied at any two places of the EPU1-CBs to achieve precise local heating, achieving a faster electric-induced shape memory. Design this style of EPUs and EPU1-CBs has great significance for overcoming the poor toughness of traditional thermosetting epoxy resins and their difficult shape plasticity after curing to form a crosslinked network. Importantly, it provides a new route for devising intrinsic toughened conductive thermosetting epoxy resins through molecular structure, greatly expanding the application field of epoxy resin.

Crosslinked polyurethane with excellent mechanical property, solvent resistance, and transparency has become one of the most widely used materials. However, the presence of chemical crosslinks makes it difficult to be reprocessed once molded, which largely restricts its recycling and reusing, resulting in the serious waste problems. Therefore, it is of great significance to prepare a new type of crosslinked polyurethane with reprocessing function. In this work, a novel reprocessable polyurethane (DOPU) based on reversible dibutanone oxime‐carbamate bonds is facilely prepared. The gel fraction of DOPUs is all higher than 95%, endowing it with excellent solvent resistance. Meanwhile, the visible light transmittance of DOPUs can reach up to 97.48%. After four thermal recycles, the tensile strength and elongation at break of recycled DOPUs can still remain at 3.21 MPa and 219.09%, respectively. Importantly, the synthesized DOPUs exhibit excellent elastic shape memory and permanent shape reconstruction properties under thermal stimulation. The dibutanone oxime‐carbamate bonds can also be degraded under UV irradiation, making this material easily degradable. Hence, this material has potential applications in coatings, elastomers, and some other fields.

Despite great progress having been made in realizing the intrinsic self-healing of thermosetting polymers based on dynamic bond crosslinking, it is difficult to achieve intrinsic self-healing of thermosetting polymers crosslinked by permanent covalent bonds due to the permanent crosslinked structures restricting the mobility of molecular chains. Herein, we present a new type of thermosetting polymer with room-temperature autonomous self-healing performance by crosslinking hydroxyl functionalized hyperbranched polymers with permanent covalent bonds. The phenomenon of swelling and insolubility in the solvent and up to 72.9% gel rate confirm the formation of a crosslinked structure; meanwhile, infrared spectroscopy and ¹³C nuclear magnetic resonance analysis results confirm that this thermosetting polymer retains the strong mobility characteristics of hyperbranched polymer chains, and the high density of hydrogen bonds formed by the hydroxyls at the ends of branching arms also have considerable dynamics at room temperature. As a result, the above combined effect promotes the realization of excellent autonomous self-healing properties at room temperature. Specifically, the polymer can recover to 24.2% of the original tensile strength within 2 min, and, as time goes by, the tensile strength gradually recovers and can eventually reach 51.9% of the original tensile strength within 4 h. Therefore, the proposed technology provides a new insight for the preparation of autonomous self-healing thermosetting polymers and broadens the range of autonomous self-healing materials to permanent covalent bond-crosslinked thermosetting polymers.

Preparation of cotton fabric with superhydrophilicity-oleophobicity in the air and superoleophobicity under water by using branched polyethyleneimine/perfluorooctanoic acid composites and its application in gravity-controlled oil-water separation.