Electromagnetic Wave Absorption Coating Material with Self-Healing Properties

Electromagnetic wave absorption coatings can effectively minimize electromagnetic radiation and are widely used in the military and civil field. However, even small scratches on the coating can lead to a large decline of absorption ability and bring serious consequences. To enhance the lifetime of electromagnetic wave absorbing coating, a kind of self-healing electromagnetic wave absorbing coating is developed by introducing host-guest interactions between the absorbing fillers and polymer matrix. After being damaged, the cracks on this coating can be healed completely with the aid of small amounts of water. Simultaneously, the electromagnetic absorbing ability of the coating is restored along with the self-healing process

Reactive Oxygen Species and Glutathione Dual Redox-Responsive Supramolecular Assemblies with Controllable Release Capability

A dual redox and biorelevant triggered supramolecular system is developed through noncovalent supramolecular inclusion interactions between the ferrocene (Fc) modified on camptothecin (CPT) and beta-cyclodextrin (beta-CD) at the end of methoxy polyethylene glycol (mPEG). With these two segments, a stable noncovalent supramolecular structure, i.e., mPEG-beta-CD/Fc-CPT, can be formed, and then self-assembled into micellar structures in water. Interestingly, these supramolecular micelles showed uniform sphere structure, high and constant drug loading content, hyper-fast redox-responsive drug release, and exhibited equal cellular proliferation inhibition toward A549 cancer cells. The cytotoxicity evaluation of mPEG-beta-CD also indicated good biocompatibility. In vivo results revealed the mPEG-beta-CD/Fc-CPT nanoparticles had higher in vivo efficacy without side effects. It is anticipated this supramolecular complex may serve as a new kind of promising alternative for drug delivery systems

UV-Blocking Coating with Self-Healing Capacity

UV-blocking coatings are necessary to protect materials from photochemical degradation, especially for organic polymers. And self-healing capacity is necessary to ensure the service time of UV-blocking coatings. Here, an UV-blocking coating (denoted as beta CD-TiO2/P(HEMA-co-BA)) with self-healing capacity is prepared successfully by copolymerizing 2-hydroxyethyl methacrylate (HEMA), butyl acrylate (BA) and functional monomers, inclusion complexes of beta-cyclodextrin (beta CD)-modified TiO2 nanoparticles, and hydroxyethyl methacrylate-adamantine (HEMA-Ad). The beta CD-TiO2/P(HEMA-co-BA) coating not only shows excellent UV-blocking property but also enhances mechanical properties and good self-healing properties. After being damaged, beta CD-TiO2/P(HEMA-co-BA) can repair scratches by adding a little water, and the UV-blocking capacity can be restored completely along with the self-healing process. Furthermore, the self-healing process is repeatable at a given place

Semi-IPNs with Moisture-Triggered Shape Memory and Self-Healing Properties

Moisture or water has the advantages of being green, inexpensive, and moderate. However, it is challenging to endow water-induced shape memory property and self-healing capability to one single polymer because of the conflicting structural requirement of the two types of materials. In this study, this problem is solved through introducing two kinds of supramolecular interactions into semi-interpenetrating polymer networks (semi-IPNs). The hydrogen bonds function as water-sensitive switches, making the materials show moisture-induced shape memory effect. The host-guest interactions (-cyclodextrin-adamantane) serve as both permanent phases and self-healing motifs, enabling further increased chain mobility at the cracks and self-healing function. In addition, these polyvinylpyrrolidone/poly(hydroxyethyl methacrylate-co-butyl acrylate) semi-IPNs also show thermosensitive triple-shape memory effect

pH and glutathione dual-triggered supramolecular assemblies as synergistic and controlled drug release carriers

A pH and glutathione (GSH) dual bio-relevant triggered supramolecular system is constructed through the non-covalent host-guest interactions between the adamantane (ADA) on camptothecin (CPT) and beta-cyclodextrin (beta-CD) on the side chain of the backbone of hyaluronic acid (HA). The obtained non-covalent supramolecular beta-CD-g-OX-HA/ADA-CPT complex could further self-assemble into a stable uniform sphere micellar structure with constant drug loading content in the extracellular environment but is cleaved in the cytosol of the cancer cells due to the acidic environment and the presence of a high concentration of GSH, resulting in a synergistic-fast pH and GSH triggered drug releasing behavior. The cytotoxicity of the supramolecular beta-CD-g-OX-HA/ADA-CPT micelles was investigated using Hep G2 cancer cells by MTT assays, which displayed that supramolecular beta-CD-g-OX-HA/ADA-CPT micelles had exhibited enhanced cellular proliferation inhibition against Hep G2 cancer cells compared to the free CPT, while the beta-CD-g-OX-HA had good cell compatibility. In vivo studies of the beta-CD-g-OX-HA/ADA-CPT micelles showed a higher in vivo efficacy without side effects and also confirmed the compatibility of the beta-CD-g-OX-HA. It is anticipated that this supramolecular complex will give the possibility to fabricate new types of bio-relevant triggered nanocarriers for cancer therapy

pH- and Thermal-Responsive Multishape Memory Hydrogel

A multistimuli-sensitive shape memory hydrogel with dual and triple shape memory properties,was prepared by grafting dansyl groups into the network of polyacrylamide (PAAM). The hydrophobic aggregation of dansyl groups acted as molecular switches, which showed reversible aggregation-disaggregation transition in aqueous solution in response to the pH or temperature change

Light-, pH- and thermal-responsive hydrogels with the triple-shape memory effect

Light-, pH- and thermal-responsive hydrogels were prepared by introducing dansyl-aggregations and azo-cyclodextrin inclusion complexes as switches. The resulting material showed dual shape memory behavior in response to light, pH or temperature, respectively, and exhibits the triple-shape memory effect in response to light and pH sequentially

A Tri-Stimuli-Responsive Shape-Memory Material Using Host-Guest Interactions as Molecular Switches

A thermo-, photo-and chemoresponsive shape-memory material is successfully prepared by introducing alpha-cyclodextrin (alpha CD) and azobenzene (Azo) into a poly(acrylate acid)/alginate (PAA/Alg) network. The tri-stimuli-responsive formation/dissociation of alpha CD-Azo acts as molecular switches freezing or increasing the molecular mobility. The resulting film herein can be processed into temporary shapes as needed and recovers its initial shape upon the application of light irradiation, heating, or chemical agent independently. Furthermore, the agar diffusion test suggests that the alpha-CD-Alg/Azo-PAA has good biocompatibility for L929 fibroblast-like cells

Shape Memory Polymers Based on Supramolecular Interactions

Shape memory polymers (SMPs), with the capability to change from one or more temporary shapes to predetermined shapes in response to an external stimulus, have attracted much interest from both academia and industries. When introducing supramolecular interactions that have been featured as dynamic and reversible into the design of novel SMPs, intriguing and unique functionalities have been engendered and thereby broaden the potential applications of the SMPs to new territories. In this review, we summarize recent progress made in SMPs based on supramolecular interactions, provide insight into the material design and shape memory mechanism, elucidate and evaluate their properties and performance, and point out opportunities and applications of SMPs

The Deeply Understanding of the Self-Healing Mechanism for Self-Healing Behavior of Supramolecular Materials Based on Cyclodextrin-Guest Interactions

Cyclodextrin (CD)-based host-guest interactions are one of the important supramolecular interactions and have been playing significant role in the design of self-healing materials due to high selectivity and dynamic equilibrium. However, a deeper understanding of the self-healing mechanism is still rare, although self-healing materials based on CD-guest interactions have many advantages. This study provides a first step for the fundamental understanding of the influence factors on self-healing behavior of materials containing CD-guest complexes. It is found that the healing motifs are CD-guest interactions. Sufficient polymer chains mobility, a small amount of water, and high inclusion constant (K) of host-guest interactions are also essential to the self-healing process. The threshold of K value is around 10(2) M-1