Multifunctional Ionic Polymers from Deep Eutectic Monomers Based on Polyphenols

Phase-Segregated Ductile Eutectogels with Ultrahigh Modulus and Toughness for Antidamaging Fabric Perception

Ionogels are extremely soft ionic materials that can undergo large deformation while maintaining their structural and functional integrity. Ductile ionogels can absorb energy and resist fracture under external load, making them an ideal candidate for wearable electronics, soft robotics, and protective gear. However, developing high-modulus ionogels with extreme toughness remains challenging. Here, a facile one-step photopolymerization approach to construct an acrylic acid (AA)-2-hydroxyethylacrylate (HEA)-choline chloride (ChCl) eutectogel (AHCE) with ultrahigh modulus and toughness is reported. With rich hydrogen bonding crosslinks and phase segregation, this gel has a 99.1 MPa Young's modulus and a 70.6 MJ m-3 toughness along with 511.4% elongation, which can lift 12 000 times its weight. These features provide extreme damage resistance and electrical healing ability, offering it a protective and strain-sensitive coating to innovate anticutting fabric with motion detection for human healthcare. The work provides an effective strategy to construct robust ionogel materials and smart wearable electronics for intelligent life.

Schiff base and coordinate bonds cross-linked chitosan-based eutectogels with ultrafast self-healing, self-adhesive, and anti-freezing capabilities for motion detection

Ion conductors offer great potential for diverse electric applications. However, most of the ion conductors were fabricated from non - degradable petroleum-based polymers with non or low biodegradability, which inevitably leads to resource depletion and waste accumulation. Fabricating ion conductors based on renewable, and sustainable materials is highly desirable and valuable. Herein, a series of eutectogels were designed through dual-dynamic-bond cross-linking among ferric iron (Fe3+), protocatechualdehyde (PA), and chitosan (CS) in 1 - allyl-3 - methylimidazole chloride ionic liquid/urea (AmimCl/urea) eutectic-based ionic liquid. Due to the presence of AmimCl/urea eutectic-based ionic liquid, the obtained CS - PA@Fe eutectogels showed excellent ionic conductivity, superior anti-freezing properties that could maintain flexibility and high electrical properties at -20 °C. Dual-dynamic-bond cross-linking of catechol-Fe coordinate and dynamic Schiff base bonds equip CS - PA@Fe eutectogels with excellent injectable, and self-healing abilities. Additionally, due to the presence of phenolic hydroxyl groups of PA, the obtained CS - PA@Fe eutectogels present good adhesiveness. Based on the CS - PA@Fe eutectogels, multifunctional flexible strain sensors with high sensitivity, stability, as well as rapid response speed at wide operating temperature ranges were successfully fabricated. Thus, this study offers a promising strategy for fabricating naturally occurring biopolymers based eutectogels, which show great potential as high-performance flexible strain sensors for next-generation wearable electronic devices.

Light-Based 3D Multi-Material Printing of Micro-Structured Bio-Shaped, Conducting and Dry Adhesive Electrodes for Bioelectronics

In this work, a new method of multi-material printing in one-go using a commercially available 3D printer is presented. The approach is simple and versatile, allowing the manufacturing of multi-material layered or multi-material printing in the same layer. To the best of the knowledge, it is the first time that 3D printed Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) micro-patterns combining different materials are reported, overcoming mechanical stability issues. Moreover, the conducting ink is engineered to obtain stable in-time materials while retaining sub-100 µm resolution. Micro-structured bio-shaped protuberances are designed and 3D printed as electrodes for electrophysiology. Moreover, these microstructures are combined with polymerizable deep eutectic solvents (polyDES) as functional additives, gaining adhesion and ionic conductivity. As a result of the novel electrodes, low skin impedance values showed suitable performance for electromyography recording on the forearm. Finally, this concluded that the use of polyDES conferred stability over time, allowing the usability of the electrode 90 days after fabrication without losing its performance. All in all, this demonstrated a very easy-to-make procedure that allows printing PEDOT:PSS on soft, hard, and/or flexible functional substrates, opening up a new paradigm in the manufacturing of conducting multi-functional materials for the field of bioelectronics and wearables.

Eutectic In Situ Modification of Polyamide 12 Processed through Laser-Based Powder Bed Fusion

Laser-based powder bed fusion (LPBF) of polymers allows for the additive manufacturing of dense components with high mechanical properties. Due to inherent limitations of present material systems suitable for LPBF of polymers and required high processing temperatures, the present paper investigates the in situ modification of material systems using powder blending of p-aminobenzoic acid and aliphatic polyamide 12, followed by subsequent laser-based additive manufacturing. Prepared powder blends exhibit a considerable reduction of required processing temperatures dependent on the fraction of p-aminobenzoic acid, allowing for the processing of polyamide 12 at a build chamber temperature of 141.5 °C. An elevated fraction of 20 wt% of p-aminobenzoic acid allows for obtaining a considerably increased elongation at break of 24.65% ± 2.87 while exhibiting a reduced ultimate tensile strength. Thermal investigations demonstrate the influence of the thermal material history on thermal properties, associated with the suppression of low-melting crystalline fractions, yielding amorphous material properties of the previously semi-crystalline polymer. Based on complementary infrared spectroscopic analysis, the increased presence of secondary amides can be observed, indicating the influence of both covalently bound aromatic groups and hydrogen-bound supramolecular structures on emerging material properties. The presented approach represents a novel methodology for the energy-efficient in situ preparation of eutectic polyamides, potentially allowing for the manufacturing of tailored material systems with adapted thermal, chemical, and mechanical properties.