Photoelectron spectroscopic study of the ethyl cyanoacrylate anion

Gel Polymer Electrolytes for Lithium Batteries: Advantages, Challenges, and Perspectives

The increasing demand for high-energy-density and safe lithium batteries has driven significant advancements in electrolyte technology. Among the various options, gel polymer electrolytes (GPEs) have emerged as a promising solution, combining the high ionic conductivity of liquid electrolytes with the structural integrity of solid-state (polymer) electrolytes. GPEs possess a hybrid structure composed of a polymer matrix, lithium salts, one or more solvents or plasticizers, and often functional additives, offering exceptional flexibility, adaptability, and performance for advanced energy storage systems. This review provides a comprehensive analysis of GPE technology for lithium batteries, covering fabrication methods, advantages, and challenges, while emphasizing potential application scenarios and the underlying mechanisms. Finally, future research directions are outlined to provide valuable insights and guidelines for advancing GPE technology.

Water-Templated Growth of Interfacial Superglue Polymers for Tunable Thin Films and In Situ Fluid Encapsulation

Thin polymer films (TPFs) are indispensable elements in numerous technologies ranging from liquid encapsulation to biotechnology to electronics. However, their production typically relies on wet chemistry involving organic solvents or chemical vapor deposition, necessitating elaborate equipment and often harsh conditions. Here, an eco-friendly, fast, and facile synthesis of water-templated interfacial polymers based on cyanoacrylates (superglues, CAs) that yield thin films with tailored properties is demonstrated. Specifically, by exposing a cationic surfactant-laden water surface to cyanoacrylate vapors, surfactant-modulated anionic polymerization produces a manipulable thin polymer film with a thickness growth rate of 8 nm min-1. Furthermore, the shape and color of the film are precisely controlled by the polymerization kinetics, wetting conditions, and/or exposure to patterned light. Using various interfaces as templates for film growth, including the free surface of drops and soap bubbles, the developed method advantageously enables in situ packaging of chemical and biological cargos in liquid phase as well as the encapsulation of gases within solidified bubbles. Simple, versatile, and biocompatible, this technology constitutes a potent platform for programmable coating and soft/smart encapsulation of fluids.

Interaction of Cyanoacrylate with Metal Oxide Surfaces (Cu, Al)

Cyanoacrylates are an extremely reactive class of adhesives. Despite their commercial use as instant adhesives, the adhesion mechanism, especially to technically relevant oxidized metal surfaces, has not yet been sufficiently investigated. In the present work, ultra-thin ethyl cyanoacrylate films are deposited on copper oxide and aluminum oxide by spin coating and cured there. Various surface sensitive spectroscopy methods are used to identify possible interactions. X-Ray photoelectron spectroscopy (XPS) indicates, among other information, hydrogen bonding of the carbonyl group to the oxidized surfaces. Metastable induced electron spectroscopy (MIES) measurements support the theory of this preferential molecular orientation. In addition, XPS shows the presence of an ionic carboxylate (COO^- ) species at the interface. Infrared reflection adsorption spectroscopy (IRRAS) measurements confirm this ionic interaction and furthermore allow to investigate the influence of water on the reaction. A possible interaction mechanism of cyanoacrylates with metal oxides could be proposed. The formation of a carboxylate species probably occurs by hydrolysis of the ethyl group via the intermediate of a carboxyl (COOH) species.

Intramolecular Photoinduced Charge Transfer and Recombination Dynamics in Vinylarene Terminated Organosilanes

We report on charge-transfer dynamics of newly designed acceptor-donor-acceptor organosilanes, with a specific focus on how donor-acceptor combination and local chemical environment can be used to control the lifetime for intramolecular charge-separation between silane electron donors and organic acceptors. In this work linear oligosilanes were capped with arene-vinyl end groups of variable electron-accepting strength: weak (diester vinyl), intermediate (ester,cyano vinyl), and strong (dicyanovinyl). Ultrafast transient absorption spectroscopy was used to characterize their structure-dependent charge-transfer and recombination behaviors. All structures exhibit similar photoinduced ultrafast spectral dynamics that we ascribe to relaxation of the nascent charge-separated excited state followed by a return to the ground state via charge recombination. We find that relaxation of the nascent "hot" charge-separated excited state scales with the strength of dipole-dipole interactions between solvent molecules and the polar arene-vinyl acceptor. Furthermore, electron-accepting strength governs whether electronic coupling dictates charge recombination rate: weak acceptors produce charge-separated states that exhibit relatively large electronic coupling for back-electron transfer (approaching the adiabatic limit) that result in fast recombination, whereas the strong and moderate-strength acceptors support more stable charge-separated states with weaker coupling and longer lifetimes. We find that recombination rates increase substantially for structures with weak and moderate-strength acceptors in cyclohexane (i.e., negligible solvent reorganization energy), which we attribute to an increased electronic coupling in a nonpolar solvent environment where charge pairs are weakly screened. In contrast, for structures with strong electron acceptors, the very low reorganization energy of cyclohexane places back-electron transfer even further into the Marcus inverted regime, with a resultant increase in charge-separation lifetime. Together these results provide critical insights on how to tune photoinduced charge-transfer behavior in organic-inorganic hybrids that have potential material applications in molecular electronics and optoelectronics.

Highly Transparent Polyethylcyanoacrylates from Approved Eco-Friendly Fragrance Materials Demonstrating Excellent Fog-Harvesting and Anti-Wear Properties

Superglue monomers belong to a family of cyanoacrylates that are known for their very rapid polymerization upon contact with moist surfaces. Their biodegradation and low toxicity make them attractive as medical and veterinary adhesives. Although the fast-acting polymerization characteristics have been successfully utilized to design nanoscale polymeric particles that can carry drugs or other inorganic nanoparticles, it constitutes a significant drawback if one desires to produce other forms of functional biodegradable acrylics, such as coatings, sheets, or nanocomposites. This is because rapid polymerization in air creates highly porous and brittle structures. Here, we address this drawback by reporting a simple and inexpensive method of fabricating highly transparent (>92%) polyethylcyanoacrylate (PECA) coatings by dispersing the monomer in a fragrance-classified green liquid, cyclopentanone. The resulting transparent coatings were hydrophilic but with slippery wetting characteristics, suitable as efficient fog-harvesting templates. Furthermore, another fragrance liquid, benzyl alcohol, is introduced as a plasticizer and co-solvent to overcome its brittleness while retaining its transparency. The same plasticized monomer solutions, dispersing low concentrations of graphene (<0.5 wt %), were allowed to self-assemble on stainless steel surfaces, forming low-friction and anti-wear dry lubricants by decreasing the steel friction coefficient and wear rate by 6- and 10-fold, respectively.

Facile and Reliable in Situ Polymerization of Poly(Ethyl Cyanoacrylate)-Based Polymer Electrolytes toward Flexible Lithium Batteries

Polycyanoacrylate is a very promising matrix for polymer electrolyte, which possesses advantages of strong binding and high electrochemical stability owing to the functional nitrile groups. Herein, a facile and reliable in situ polymerization strategy of poly(ethyl cyanoacrylate) (PECA) based gel polymer electrolytes (GPE) via a high efficient anionic polymerization was introduced consisting of PECA and 4 M LiClO₄ in carbonate solvents. The in situ polymerized PECA gel polymer electrolyte achieved an excellent ionic conductivity (2.7 × 10^-3 S cm^-1) at room temperature, and exhibited a considerable electrochemical stability window up to 4.8 V vs Li/Li⁺. The LiFePO₄/PECA-GPE/Li and LiNi_1.5Mn_0.5O₄/PECA-GPE/Li batteries using this in-situ-polymerized GPE delivered stable charge/discharge profiles, considerable rate capability, and excellent cycling performance. These results demonstrated this reliable in situ polymerization process is a very promising strategy to prepare high performance polymer electrolytes for flexible thin-film batteries, micropower lithium batteries, and deformable lithium batteries for special purpose.

The role of local chemical hardness and van der Waals interactions in the anionic polymerization of alkyl cyanoacrylates

The polymers are stabilized appreciably by intra-chain dispersion forces. Localization of negative charge imparts sufficient local hardness for polymerization to continue independently of chain length.