Noncovalent Network Research Articles

Co-deposition of tannic acid and bottle-brush polymer to construct stable antifouling surface via hydrogen-bonding

The convenient preparation and excellent stability are two specific demands for antifouling surfaces. We designed a hydrogen-bonded network composed of tannic acid (TA) and bottle-brush polymer (BBP) to form an antifouling coating on diverse substrates. The BBP contained polyurethane backbone and polyethylene glycol (PEG) side chains which provided abundant hydrogen bond acceptors. Molecular dynamics (MD) simulation, 2D-IR and 1H NMR spectra confirmed that TA could interact with both the backbone and side chains of BBP. Owing to the strong affinity of TA to substrates and the hierarchical structure of bottle-brush polymer, TA/BBP coating possessed more intricate non-covalent network than TA/linear polymer coating and was more stable at physiologic pH. The excellent antifouling properties against serum albumin, red blood cells, fibroblasts and bacteria were demonstrated using different techniques. This work provided a strategy to prepare a stable antifouling coating relying solely on the hydrogen-bonded network of TA and BBP. Additionally, TA/BBP coating could be completely detached by strongly basic solution due to the dissociation of TA, which provided a possibility of cleaning and recycling substrates if necessary.

Diphenylene Iodonium as a Prominent Halogen Bond Donor: The Case of Human Monoamine Oxidase B.

Herein we have investigated the formation and interplay of several noncovalent interactions (NCIs) involved in the inhibition of human monoamine oxidase B (MAO B). Concretely, an inspection of the Protein Data Bank (PDB) revealed the formation of a halogen bond (HlgB) between a diphenylene iodonium (DPI) inhibitor and a water molecule present in the active site, in addition to a noncovalent network of interactions (e. g. lone pair-π, hydrogen bonding, OH-π, CH-π and π-stacking interactions) with surrounding protein residues. Several theoretical models were built to understand the strength and directionality features of the HlgB in addition to the interplay with other NCIs present in the active site of the enzyme. Besides, a computational study was carried out using DPI as HlgB donor and several electron rich molecules (CO, H2O, CH2O, HCN, pyridine, OCN-, SCN-, Cl- and Br-) as HlgB acceptors. The results were analyzed using several state-of-the-art computational tools. We expect that our results will be useful for those scientists working in the fields of rational drug design, chemical biology as well as supramolecular chemistry.

Chitinous Bioplastic Enabled by Noncovalent Assembly.

Natural polymeric-based bioplastics usually lack good mechanical or processing performance. It is still challenging to achieve simultaneous improvement for these two usual trade-off features. Here, we demonstrate a full noncovalent mediated self-assembly design for simultaneously improving the chitinous bioplastic processing and mechanical properties via plane hot-pressing. Tannic acid (TA) is chosen as the noncovalent mediator to (i) increase the noncovalent cross-link intensity for obtaining the tough noncovalent network and (ii) afford the dynamic noncovalent cross-links to enable the mobility of chitin molecular chains for benefiting chitinous bioplastic nanostructure rearrangement during the shaping procedure. The multiple noncovalent mediated network (chitin-TA and chitin-chitin cross-links) and the pressure-induced orientation nanofibers structure endow the chitinous bioplastics with robust mechanical properties. The relatively weak chitin-TA noncovalent interactions serve as water mediation switches to enhance the molecular mobility for endowing the chitin/TA bioplastic with hydroplastic processing properties, rendering them readily programmable into versatile 2D/3D shapes. Moreover, the fully natural resourced chitinous bioplastic exhibits superior weld, solvent resistance, and biodegradability, enabling the potential for diverse applications. The full physical cross-linking mechanism highlights an effective design concept for balancing the trade-off of the mechanical properties and processability for the polymeric materials.

Influence of Lowering the pH Value on the Generation of Fibrous Structures of Protein Gels with Different Network Types.

High-moisture extrusion of plant proteins to create meat-like structures is a process that has met with increasing attention in the recent past. In the process, the proteins are thermomechanically stressed in the screw section of the extruder, and the resulting protein gel is structured in the attached cooling die. Various protein sources, notably soy protein isolate (SPI) and wheat gluten, are used to form gels with different networks: SPI creates a physical, non-covalent network, while gluten forms a chemical, covalent one. The food industry frequently adds weak acids to modify taste and shelf life. However, it is known that a change in pH affects the gelation behavior of proteins because the repulsive forces within and between the proteins change. The research reported here was carried out to investigate for the two proteins mentioned the influence of pH modification by the addition of citric acid and acetic acid on gel formation and the meat-like structures produced. For this purpose, materials and parameters were screened using a closed cavity rheometer, followed by extrusion trials at pH 7.36-4.14 for SPI and pH 5.83-3.37 for gluten. The resulting extrudates were analyzed optically and mechanically, and protein solubility was tested in a reducing buffer. For both protein systems, the addition of acid results in less pronounced meat-like structures. At decreasing pH, the complex viscosity of SPI increases (from 11,970 Pa·s to 40,480 Pa·s at 100 °C), the generated gel becomes stronger (strain decreased from 0.62 to 0.48 at 4.5 × 105 Pa), and the cross-linking density grows. For gluten, a decreasing pH results in altered reaction kinetics, a more deformable resulting gel (strain increased from 0.7 to 0.95 at 4.5 × 105 Pa), and a decreased cross-linking density. Solubility tests show that no additional covalent bonds are formed with SPI. With gluten, however, the polymerization reaction is inhibited, and fewer disulfide bonds are formed.

Synthesis and Characterization of Responsive Antimicrobial Materials for Chronic Wound Management

Chronic wound treatment requires the ability to regulate the wound healing process and mitigate the propagation of bacterial infection with constant monitoring, in real-time. The need for multi-functional wound management materials has emerged as a significant research area with promise shown in the incorporation of antimicrobial agents within responsive polymeric materials to elicit signals providing dynamic information about the healing process. Traditional wound dressings provide a barrier between the outside environment and the wound; however, these methods are increasingly becoming less effective. Hydrogels synthesized from natural biopolymers have emerged due to their intrinsic properties such as biodegradability and non-cytotoxicity and enhanced from their well-defined, three-dimensional, non-covalent networks ideal for modification and functionalization to create “micro-reactors.” Previous work focused on the strategic design of an alginate-based hydrogel containing dual functional additives (i.e., amino acids) paired with photochemically prepared Ag- and Cu-TiO2 nanoparticles (Ag/Cu-NPs) to understand the synergistic interactions of the polymer chains, cross-linkers, and additives. The antimicrobial effectiveness of the composite was examined using an epi-fluorescent optical tweezer to measure the rates of bacterial cell death. Results showed that with the incorporation of the NPs there is a decrease in green signal (live cells) within 1 hour of exposure. Furthermore, the healing rates of simulated wounds using human dermal fibroblasts were explored along with changes in the expression of growth factors that promote wound healing, such as collagen and TGF-b. This work focuses on a two-layer responsive material with a wound-healing layer and a conductive layer formed through the secondary functionalization of the composite system through a metal-coordination-assisted photopolymerization of conductive polymers (i.e. aniline). Preliminary results show there is uniform polymeric chain growth seen in enhanced charge transfer through the matrix upon an applied voltage. Studies have also been conducted to measure the impact of saturation of the bandage through simulated wound exudate that revealed once saturation occurs, the passing of electricity between the ions found in wound exudate carried current through the composite, increasing the conductivity, leading to the signaling of an LED prompting replacement. The resulting two-layer nanocomposite system then functions as a responsive, antimicrobial wound healing material capable of eliminating constant monitoring with application in healthcare and home settings.

Stimulus-Induced Relief of Intentionally Incorporated Frustration Drives Refolding of a Water-Soluble Biomimetic Foldamer.

Frustrated, or nonoptimal, interactions have been proposed to be essential to a protein's ability to display responsive behavior such as allostery, conformational signaling, and signal transduction. However, the intentional incorporation of frustrated noncovalent interactions has not been explored as a design element in the field of dynamic foldamers. Here, we report the design, synthesis, characterization, and molecular dynamics simulations of the first dynamic water-soluble foldamer that, in response to a stimulus, exploits relief of frustration in its noncovalent network to structurally rearrange from a pleated to an intercalated columnar structure. Thus, relief of frustration provides the energetic driving force for structural rearrangement. This work represents a previously unexplored design element for the development of stimulus-responsive systems that has potential application to materials chemistry, synthetic biology, and molecular machines.

Mucosa-Inspired Electro-Responsive Lubricating Supramolecular-Covalent Hydrogel.

Enabling the living capability of secreting liquids dynamically triggered by external stimuli while maintaining the bulk frame is a significant challenge for mucosa-inspired hydrogels. A mucosa-inspired electro-responsive hydrogel is developed in this study using the synergy between electro-responsive silk supramolecular non-covalent networks and covalent polyacrylamide and polyvinyl alcohol polymer networks. The formed supramolecular-covalent hydrogel exhibits a partial gel-sol transition upon the application of an electric field, and the liquid layer on the hydrogel surface near the cathode is used to mimic the mucus-secreting capability to regulate lubrication. The electro-responsive lubricating process can operate under a safe voltage and exhibits good reversibility. It is also a universal strategy is to construct an electro-responsive hydrogel by introducing an electro-responsive supramolecular network into the polymer network. This mucosa-inspired electro-responsive supramolecular-covalent hydrogel offers a promising method for designing soft actuators or robots that can regulate lubrication using an electric strategy. This article is protected by copyright. All rights reserved.

Intrinsically Stretchable Conductive Self-Healable Organogels for Strain, Pressure, Temperature, and Humidity Sensing.

Intrinsically stretchable conductive self-healable organogels containing poly(lipoic acid), Al3+ ion, tannic acid, and reduced graphene oxide are produced in this report. These noncovalent networks interlocked through physical (hydrogen and coordination) bonds offered high stretchabilities and mechanical strengths as well as fast self-healing behaviors. The optimum organogel-based sensor showed outstanding pressure sensitivities (0.94 kPa-1 up to 10 and 1.07 kPa-1 for 10-50 kPa) and high strain responses (corresponding gauge factors of 1.1 and 0.4 for 0-50 and 50-100% stretching ratios). This organogel also revealed high stabilities at ambient atmosphere due to the presence of binary solvents of dimethyl sulfoxide and glycerol. Additionally, this stretchable thermistor displayed remarkable two-stage sensitivities of -2.6 and -0.4%/°C ranging over 0-30 and 30-80 °C, respectively. Besides, the signal variations of water droplet addition and removal with different temperatures were recorded by the organogel sensor to elucidate the practical applicabilities as a temperature sensor. Moreover, the organogel was utilized to demonstrate humidity sensing, where individual sensitivities of 0.89 and 0.55 were obtained in the respective relative humidity ranges of 10-30 and 40-90%. In the meanwhile, the sensor device illustrated distinct humidity signals during respiration monitoring of nose and mouth breathing detection. Accordingly, these quad-functional sensor applications in strain, pressure, temperature, and humidity detection enable this gel to act as a promising material for future multifunctional flexible electronics.

Multifunctional Starch-Based Sensor with Non-Covalent Network to Achieve "3R" Circulation.

With the consumption of disposable electronic devices increasing, it is meaningful but also a big challenge to develop reusable and sustainable materials to replace traditional single-use sensors. Herein, a clever strategy for constructing a multifunctional sensor with 3R circulation (renewable, reusable, pollution-reducing biodegradable) is presented, in which silver nanoparticles (AgNPs) with multiple interactions are introduced into a reversible non-covalent cross-linking network composed of biocompatible and degradable carboxymethyl starch (CMS) and polyvinyl alcohol (PVA) to simultaneously obtain high mechanical conductivity and long-term antibacterial properties by a one-pot method. Surprisingly, the assembled sensor shows high sensitivity (gauge factor up to 4.02), high conductivity (0.1753 S m-1 ), low detection limit (0.5%), long-term antibacterial ability (more than 7 days), and stable sensing performance. Thus, the CMS/PVA/AgNPs sensor can not only accurately monitor a series of human behavior, but also identify handwriting recognition from different people. More importantly, the abandoned starch-based sensor can form a 3R circulation. Especially, the fully renewable film still shows excellent mechanical performance, achieving reusable without sacrificing its original function. Therefore, this work provides a new horizon for multifunctional starch-based materials as sustainable substrates for replacing traditional single-use sensors.

Low density lipoprotein-pectin complexes stabilized high internal phase pickering emulsions: The effects of pH conditions and mass ratios

The present work aimed to explore the feasibility of using egg yolk low density lipoproteins (LDL) as naturally occurring nanoparticles to prepare high internal phase Pickering emulsions (HIPEs), and to understand the role of pectin (PE) as a natural food thickener in improving the emulsifying stability to prepare HIPEs. Colloidal complexes were formed spontaneously via electrostatic interactions upon mixing PE and LDL at acidic pH condition. The colloidal characteristics of LDL-PE complexes were studied by dynamic light scattering method, Fourier transform infrared spectroscopy and viscosity measurements, as well as interfacial activities. Lastly, the capability of complexes as a stabilizer to prepare HIPEs was then comprehensively investigated as functions of pH conditions and mass ratios of LDL and PE. The results indicated that the particle sizes and surface activities of LDL-PE complexes were highly dependent on the electrostatic interactions. The interactions between LDL and PE slightly reduced at neutral pH conditions or higher concentrations of PE, which were more favorable to form stable particles with smaller size and higher surface activity, and thus greater stability of HIPEs. Although the interfacial tensions of LDL increased with the existence of PE, the stability of LDL-PE stabilized HIPEs (LP-HIPEs) was greatly enhanced compared with the free LDL stabilized ones. LDL and PE formed non-covalent network among the emulsion droplets and the oil-water interface of HIPEs, inducing stable gel structure. Droplet size analysis and morphological observation under optical microscopes together with digital photos revealed the homogenous emulsion droplets in a strong gel geometry. Gel-like elastic network structure was confirmed by rheological measurements, and the thick coating layer of LDL-PE complexes on the oil-water interface was further visualized by confocal laser scanning microscope. Our findings are innovative and offer new opportunities to prepare HIPEs from all natural ingredients for future applications in the food industry. • Low density lipoprotein-pectin (LDL-PE) complexes were able to stabilize HIPEs. • Pectin played critical roles in the formation of stable gel-like structure in HIPEs. • Rheological data and microscopical images confirmed the strong gel network. • The HIPEs showed exceptional stability in centrifugation and long-term storage tests. • LDL-PE exhibited superior emulsifying and stabilization capability than LDL alone.

External Heavy-Atom Activated Phosphorescence of Organic Luminophores in a Rigid Fluid Matrix

Growing attention has been paid to pure organic room-temperature phosphorescence (RTP). Although an insufficient population and fast nonradiative decay of triplet excitons are avoided in recent endeavors, complicated synthesis and limited universality still hinder its development. Further, fluid RTP materials are more difficult to design because of faster nonradiative relaxation. Herein, a deep eutectic mixture of glucose and choline, a stable supercooled liquid at room temperature, is employed as a matrix. Direct transformation from commercial fluorescent dyes to RTP fluid is realized by doping without modifications. The excited triplet states are generated by an external heavy atom, while the rigid noncovalent network stabilizes them with both functions intrinsic to the liquid matrix. Modulation of matrix components also results in nearly white light emission of a single dye. This study presents a general strategy to design fluid RTP materials starting from the vast library of fluorophores.

Bioinspired fabrication of self-recovery, adhesive, and flexible conductive hydrogel sensor driven by dynamic borate ester bonds and tannic acid-mediated noncovalent network

Conductive polymer hydrogels have received enormous attention because of their promising applications in healthcare monitoring, soft robots, and wearable electronics. Development of hydrogel sensor with strong mechanical properties, excellent sensing capabilities, self-healing and adhesive properties is highly desirable and still remains a critical challenge. Herein, we report a borax crosslinked flexible hydrogel based on polyvinyl alcohol (PVA), sodium alginate (SA), and tannic acid (TA) modify barium titanate (BT) nanoparticles (T@BT) via a facile one-pot method. The crosslinking network was formed by dynamic reversible borate ester bond and TA-enabled interactions including hydrogen bonds and coordination bonds, which endowed the hydrogel with excellent self-healing and mechanical properties. Meanwhile, the combination of functional catechol groups in TA with the significantly improved cohesion of the hydrogel enabled the hydrogel to exhibit strong and residue-free adhesion to a variety of inorganic and organic materials. The adhesion strength to wood was up to 67.5 kPa. Furthermore, the addition of the T@BT not only rendered the hydrogel highly conductive (1.91 S/m) and sensitive for sensing, but also synergistically enhanced the toughness (587.1 KJ/m3) of the hydrogel. This work provides new ideas for the preparation of multifunctional conductive hydrogels.

Responsive emulsion gels of glycyrrhizic acid and alanine for cigarette capsules

Low-cost and simplified synthesis process of capsule cigarettes for wider application has received more and more attention. Water phase is suggested to be introduced into the oil content of cigarette capsules in consideration of the cost. The stimuli produced during the smoke can contribute to the phase transition with further flavor release. Here, a kind of multiple stimuli-responsive cigarette capsules based on emulsion gels was designed. The oil-in-water emulsion gels stabilized by glycyrrhizic acid (GA) and alanine (Ala) were prepared through simple one-pot emulsification at high temperature (80 °C) followed with a subsequent cooling. The non-covalent network between GA and Ala endowed emulsion gels with temperature and stress responsiveness, while the CO2 responsiveness was realized by the electrostatic complex formed between the amino group of Ala and the carboxyl group of GA. The rheological behaviors of emulsion gels were evaluated, suggesting that emulsion gels with self-recovery property and temperature responsiveness can satisfy the demands of cigarette capsules application such as the long-distance transportation and flavor release during the smoke. It is found that the oil-soluble flavor loaded in the emulsion gels can be controllably released in response to stimuli that generated during the smoking process, therefore reducing the additional introduction of external stimuli. Our work provides a novel strategy for preparing cigarette capsules with simple synthesis, low cost and eco-friendly characteristics.

Chitosan-enhanced nonswelling hydrogel with stable mechanical properties for long-lasting underwater sensing

Existing anti-swelling hydrogels with poor mechanical strength restrict their underwater human monitoring as wearable electronic sensing equipment. Herein, a nonswelling double network (DN) hydrogel with strong self-recoverability (97.22%) was developed by adding chitosan (CS) to poly(acrylic acid-2-methoxyethyl acrylate)-Fe3+ [P(AA-MEA)-Fe] network. Owing to the introduction of CS, the hydrogel displayed excellent nonswelling properties under aqueous solutions (pH = 1, 4 and 7), physiological saline, seawater, dodecane, n-hexane and chloroform. Besides, CS improved mechanical properties of hydrogel through non-covalent network (large stretchability of 1199%, tensile strength of 0.462 MPa and toughness of 2.01 MJ/m3). Surprisingly, the hydrogel still reached the extensibility (1072%) and tensile stress (0.467 MPa) even after immersing in water for 7 days. Fabricating hydrogel as flexible strain sensor, periodic real-time signals of human movements (e.g., joint actions and electronic skin touching) were accurately monitored under the water and seawater. The nonswelling P(AA-MEA)-CS-Fe hydrogel shows huge potential in underwater sensing.

Double noncovalent network chitosan/hyperbranched polyethylenimine/Fe3+ films with high toughness and good antibacterial activity.

The application of pure chitosan films is significantly limited due to their poor mechanical properties. In this study, a novel type of chitosan/hyperbranched polyethylenimine (CHP) and chitosan/hyperbranched polyethylenimine/Fe3+ (CHPF) films with high toughness and good antibacterial activity were prepared through a noncovalent crosslinking method. From the tensile test results, the strain and toughness of the CHP film increased by 798.1% and 292.3%, respectively, compared with pure chitosan film, after the addition of 20% hyperbranched polyethylenimine (HPEI). The addition of trace metal iron ions (3 mg) forms a metal coordination bond with the amine group on HPEI, as well as the hydroxyl group and amine group on chitosan, and develops a double noncovalent bond network structure with hydrogen bonding, which further enhances the mechanical tensile strength of the chitosan-based film, with an increase of 48.4%. Interestingly, HPEI and Fe3+ can be used as switches to increase and decrease the fluorescence property of chitosan, respectively. Furthermore, the CHP and CHPF films showed good antibacterial activity against S. aureus and E. coli.

Tough and strong biomimetic soy protein films with excellent UV-shielding performance

To develop strong and tough bio-based composite films as replacements for synthetic polymer films is challenging. Based on the strong adhesion of the comb-like structure of geckos’ feet or pressure-sensitive resins on substrates, a comb-like polymer-aminated dialdehyde starch (A-DAS) was designed and prepared from polyamide polyamine polymer and dialdehyde starch via a Schiff-based reaction, and then combined with soy protein isolate (SPI) to develop a protein-based film. The comb-like A-DAS exhibited strong adhesion with SPI molecules by forming multiple hydrogen bonds, which created a noncovalent network that improved both the strength and toughness of the resultant film. The results showed that after integrating A-DAS (SPI:A-DAS weight ratio of 2:1), the tensile strength of the film dramatically increased by 1072.2% to 25.09 MPa, which is markedly better than that of other reported protein-based films. The toughness of the SPI/A-DAS film increased to 16.74 MJ/m 3 . Notably, the modified film could block 100% of the ultraviolet transmittance (<400 nm) owing to the imine group in A-DAS. This strategy offers a simple and effective way to construct strong and tough composite materials with ultraviolet-barrier performance, indicating potential applications in tissue engineering, hydrogels, and coating modification. • A high-performance SPI-based film was prepared inspired by gecko feet and PSAs. • Strong hydrogen bonds promoted the toughness of the SPI-based film. • The tensile strength and toughness of the films improved by 1072.2% and 307.3%. • The SPI-based film exhibited UV-shielding properties for packaging.

A Missense Mutation (R723H) in the Head Motor Domain of β-MYH7 gene in an Indian HCM Patient and Phenotypic Plasticity

Mutations in the β-MYH7 gene are one of the major causes that lead to cardiomyopathies. However, to differentiate a causative nsSNP and its impact on protein structure remains a major challenge. In the present study, we detected a missense mutation Arg723His in the head motor domain of β-MYH7 in a HCM patient, and it was absent in 207 healthy individuals. The mutant (R723H) has been found to alter an evolutionarily conserved amino acid. In addition, the mutant (R723H) was predicted pathogenic by Polyphen-2 and SIFT bioinformatic tools. Further, the superimposed 3D structure of the mutant (p.His723 homology model) with native (p. Arg723) displayed the root means square deviation (RMSD) of ~3.38A0. We know that the non-covalent interactions such as hydrophobic, electrostatic, Van der Waals, and hydrogen bonds between amino acids are at the heart of stabilizing protein structures. Here, we demonstrated how the mutant (p.His723) has disrupted a critical non-covalent interactions network at the mutation site and may contribute to the disease phenotype. Hence, our findings in the future could pave the way for developing small molecular modulators or myosin-targeted therapies for heart failure.

Development of "Imprint-and-Report" Dynamic Combinatorial Libraries for Differential Sensing Applications.

Sensor arrays using synthetic receptors have found great utility in analyte detection, resulting from their ability to distinguish analytes based on differential signals via indicator displacement. However, synthesis and characterization of receptors for an array remain a bottleneck in the field. Receptor discovery has been streamlined using dynamic combinatorial libraries (DCLs), but the resulting receptors have primarily been utilized in isolation rather than as part of the entire library, with only a few examples that make use of the complexity of a library of receptors. Herein, we demonstrate a unique sensor array approach using "imprint-and-report" DCLs that obviates the need for receptor synthesis and isolation. This strategy leverages information stored in DCLs in the form of differential library speciation to provide a high-throughput method for both developing a sensor array and analyzing data for analyte differentiation. First, each DCL is templated with analyte to give an imprinted library, followed by in situ fluorescent indicator displacement analysis. We further demonstrate that the reverse strategy, imprinting with the fluorescent reporter followed by displacement with each analyte, provides a more sensitive method for differentiating analytes. We describe the development of this differential sensing system using the methylated Arg and Lys post-translational modifications (PTMs). Altogether, 19 combinations of 3-5 DCL data sets that discriminate all 7 PTMs were identified. Thus, a comparable sensor array workflow results in a larger payoff due to the immense information stored within multiple noncovalent networks.

Aggregate Engineering in Supramolecular Polymers via Extensive Non-covalent Networks

Aggregate engineering of non-covalent networks enables thermo-mechanical versatility of supramolecular polymers, particularly the stimuli-responsive phase transitions and intrinsically damage-healing abilities. However, most non-covalent networks are vulnerable at elevated temperatures, which significantly suppress the robustness of supramolecular polymers. Herein, ureidocytosine (UCy) motifs that can form extensive non-covalent networks and thus robust molecular aggregates via multivalent hydrogen bonds and aromatic stackings, are proposed to enable precise programming of the thermo-mechanical versatility. Molecular simulations reveal that the enthalpic contributions from the UCy aggregates play dominant roles to compensate the entropic loss from the redistributions of polymeric spacers and stabilize the non-covalent networks over wide temperature windows. Such aggregate-level strategy offers prospects for applications which require thermo-mechanical versatility of supramolecular polymers, such as 3D printing, microfabrication and damage-healing coating.

C36 Dimer Fatty Acid-Based Flexible Unsaturated Polyester Resin: Improvement of Properties by Adjusting the Intermolecular Crosslinking Structure

The efficient use of vegetable oil and animal oil resources has enormous economic and ecological value and has attracted tremendous interest in the field of bio-based synthetic polymers in the past years. Given that conventional oil and their derivative polymers are subject to unsatisfactory mechanical properties or short-term use, these materials are not suitable for practical applications. Herein, a series of novel C36 dimer fatty acid-based unsaturated polyester resins with covalent and noncovalent networks were prepared by C36 dimerized fatty acid-based unsaturated polyester and crosslinking agents (styrene, acrylic acid, methacrylic acid, etc.). Owing to crosslinking structure of the polymers, their stable covalent bonds and hydrogen bonds, the matrix exhibits outstanding mechanical properties, including increased stretch ability (52.6% of unsaturated polyester resin (UPR)-St/acrylic acid (AA), 57.3% of UPR-St/methylacrylic acid (MAA)), tensile strength (15.2 MPa of UPR-St/AA, 17.1 MPa of UPR-St/MAA), elasticity modulus (327.1 MPa of UPR-St/AA, 316.8 MPa of UPR-St/MAA), and flexural strength (14.8 MPa of UPR-St/AA, 33.4 MPa of UPR-St/MAA). Micromorphological investigations indicated that the fracture features of the resin changed from brittle to ductile. Additionally, the resin is shown to possess an impressive thermal stability, solvent resistance, and certain autonomous self-healing properties.