Articles
ACS Applied Polymer Materials (26376105)(3)
Soft robots with intelligent shape-changing capabilities and spatially controlled actuation are essential for enhancing their performance. Here, three-dimensional printing of self-healing, near-infrared light-responsive shape memory granular hydrogels (SLSH) was introduced. The hydrogels were formulated using four distinct microgels: β-cyclodextrin-functionalized microgels (CDMGs) and 1-adamantylamine-functionalized microgels (AMGs) to promote host-guest physical interactions for self-healing and shear-thinning properties; polydopamine-functionalized microgels (PMGs) for photothermal conversion and antibacterial activity; and microgels with epoxy groups (MG) to enable chemical cross-linking with Jeffamine, forming a shape memory framework. The shear-thinning, shape memory, and self-healing characteristics were influenced by physical interactions within the ink as well as the chemical bonds formed after postprinting treatment. The viscosity and yield strength of the inks showed an increasing trend with a higher fraction of CDMG and AMG, indicating stronger reversible attractions within the jammed assembly of particles. Upon irradiation with an intensity of 1000 mW·cm-2 for 2 min, the internal temperature of the hydrogels increased to 38.2-43.0 °C, depending on the hydrogel type. For SLSH70, a distinct melting peak was recorded at 35-41 °C, associated with the melting of crystalline domains of Jeffamine, which was essential for the thermal shape recovery of the construct. After 1 h of fixation, the hydrogels SLSH30, SLSH50, and SLSH70 demonstrated a shape-fixing efficiency of 98.22 ± 0.45, 99.38 ± 0.68, and 98.54 ± 0.26%, respectively, with shape recovery efficiency approaching approximately 100%. During the self-healing process, complete reattachment occurred after 24 h at 25 °C for SLSH30, while the other samples exhibited a weaker healing ability. Finally, the results of antibacterial investigations highlighted the synergistic effects of PMG’s inherent antibacterial properties and its photothermal activity within the bacterial environment. © 2025 American Chemical Society.
Polymer Composites (02728397)
Waterborne polyurethane (WPU) is one of the most applicable products used in various industries to manufacture smart coatings with self-healing ability due to its being environmentally friendly. However, the self-healable WPU coatings suffer from long healing times, low transparency, and poor physicochemical properties. Herein, ionic nanocomposite coatings were prepared based on SiO2-nanoscale ionic materials (SiO2-NIMs) and novel WPU, with fast self-healing ability, high transparency, and UV-blocking performance. We demonstrate that SiO2-NIMs can significantly act as a unique healing agent in the WPU due to their fluid 3D-dynamic networks of hard core-corona (SiO2-SO3−) and soft segments (canopy). The optical micrographs show the WPU film containing 3 phr SiO2-NIMs completely repaired after 20 min at 50°C. The tensile test illustrates that elongation at break, tensile strength, and toughness values of the healed sample recovered 78.2%, 94.2%, and 69.3% of the original film, respectively. The differential scanning calorimetry, x-ray diffraction, and dynamic mechanical-thermal tests were applied to confirm core-corona-canopy segments' hardening and excellent damping behavior in the WPU matrix. The thermogravimetric and tensile analyses demonstrate that SiO2-NIMs can enhance the thermal stability and mechanical properties of WPU. This study introduces a novel strategy based on SiO2-NIMs for preparing self-healing polymers with outstanding physicochemical properties. Highlights: Synthesized novel WPU based on anionic Congo red. Introducing a novel strategy-based SiO2-NIMs for self-healing of coatings. Enhancement of self-healing and thermo-mechanical properties of the WPU. Introducing healable and UV-blocking abilities of ionic nanocomposite coating. © 2025 Society of Plastics Engineers.
Biomaterials Advances (27729508)
Herein, Polydopamine-modified microgels and microgels incorporated with superficial epoxy groups were synthesized and applied as precursors for the fabrication of four granular hydrogels. To enhance the tissue adhesiveness, a ternary deep eutectic solvent was synthesized to activate the muscle amine functional groups facilitating the formation of robust N–C bonds at ambient conditions. At a certain shear rate of 10 s−1, hydrogel DMG displayed a viscosity of 9×103 Pa/s, representing the highest complex viscosity among the tested hydrogels primarily driven by quinone groups in PDA which enhanced reversible interactions, thereby increasing particle cohesion. Moreover, the intersection point escalating from about 4×103 to approximately 9×104 as the concentration of DMG increased from 0 % (for MG) to 70% (7D3MG) by weight. There was a decrease in adhesion strength from 0.45 ± 0.08 N in MG to 0.39 ± 0.16 N, 0.35± 0.18 N, and 0.33 ± 0.15 N for 3D7MG, 7D3MG, and DMG respectively, suggesting that MG was capable of forming numerous covalent bonds, thereby enhancing its adhesion to the substrate. The type of eutectic mixture affected the electrical conductivity and a very important point was the changes in resistance value with time. For MG catalyzed by [DES]AZG, the resistance increased only by 1.3 % (from 3.37 to 3.81 kΩ) at day 3 and 37.09 % (from 3.37 to 4.62 kΩ) at day 5. The 3D7MG hydrogel exhibited superior therapeutic efficacy toward diabetic wound regeneration. The proliferation index value for 3D7MG-[DES]AZG and 3D7MG-[DES]AG were calculated 42.3 % and 58.6 %, respectively, while the control group exhibited a lower value of 37.8 %. © 2024 Elsevier B.V.
Polymer Composites (02728397)46(9)pp. 7858-7881
Epoxy resins (EP), as significant thermosetting macromolecules, are widely used in various engineering applications due to their wide range of properties. However, the poor control over curing process of EP, limits their manufacturing process. Here, a SiO2-nanoscale ionic materials (SiO2-NIMs)/EP nanocomposite was prepared. The Friedman, Kissinger, Ozawa, Málek, and Friedman autocatalytic models were used to determine kinetic parameters and reaction models, which demonstrates that the SiO2-NIMs improve the curing characteristics of EP through an exclusive mechanism. The solvent role of SiO2-NIMs decreased viscosity and increased reactant mobility, leading to increased curing reactivity. The multi-function groups in the corona-canopy make multiple hydrogen bonding and proton transfer interactions in EP resin, leading to the autocatalytic curing mechanism and effectiveness of treatments. The frequency factor of EP increased by 9% with the addition of SiO2-NIMs. The differential scanning calorimetry tests revealed that SiO2-NIMs decreased Tonset and Tpeak compared to EP. The non-isothermal rheometric mechanical spectrometery (RMS) test indicated that SiO2-NIMs decreased the Tgel of EP resin from 75 to 71°C and increased the initial storage modulus by 90.9%. This study introduces SiO2-NIMs as significant fillers to enhance control over the process conditions and curing kinetic of EP resin for advanced applications such as aerospace and satellite industries. Highlights: Introducing new catalyst based on 3D-dynamic networks strategy of SiO2-NIMs. The SiO2-NIMs show great potential in improving curing characteristics of EP. The SiO2-NIMs increase the frequency factor of EP by 9%. The RMS test indicated SiO2-NIMs increased initial storage modulus by 90.9%. The Fourier transform infrared spectroscopy analysis indicated that SiO2-NIMs accelerate curing process of EP. © 2025 Society of Plastics Engineers.
Deep eutectic solvents have attracted considerable attention due to their economic and environmental benefits. This study investigates the role of reactive DESs in the synthesis of polyurethane coatings. DESs synthesized from Tetrabutylammonium bromide (TBAB) as a hydrogen-acceptor and Poly (ethylene glycol) and Ascorbic acid (AA) as hydrogen-donors, were used as assistant platforms and reactive agents for the synthesis of new biodegradable crosslinked PU-coatings via a solvent-free process. Cured PUs were characterized by FTIR, DSC, TGA, and DMTA techniques, as well as gel-content, swelling-index, biodegradation, scratch, and hardness tests. The results show that these DESs have played a splendid multi-task role that acted as non-volatile solvents and reactive monomers as well. They also facilitated curing reaction, improved flexibility, biodegradability, swelling-index, and resistance to scratch of PU-based DESs compared to pristine PU. PU samples synthesized in the presence of [DES]PEG/TBAB (P2) and [DES]AA/TBAB (P3) showed increased flexibility and damping properties (78, 26 Shore D—0.9, 1.3 Tanδ), biodegradability (81%, 60%), swelling-index (105%, 150%) and scratch resistance (3.8, 4.5 N), by about 69%, 52%, 36%, 48%, and 26% compared to the control sample (P1), respectively. Agar diffusion tests showed antibacterial activity of PU-DESs against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. This research highlights DESs as promising platforms to enhance the properties of PU coatings for the creation of eco-friendly, high-performance antiseptic coatings. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
