查找使用阿拉丁产品的科研文献

A triple-network hydrogel synergistically constructed via hydrophobic interactions, hemicellulose-mediated Diels-Alder bonds, and Fe3+ coordination for flexible sensors and TENGs

Lihui Zhao,Shibo Wang,Haoran Zhang,Siheng Wang,He Liu,Xu Xu,Bowen Yan

Polyacrylamide (PAM) -based conductive hydrogels show immense promise for flexible wearable sensors and triboelectric nanogenerators (TENGs). However, integrating superior mechanical properties, strong adhesion, high conductivity, and fatigue resistance within a single system remains a formidable challenge. Herein, a triple-network hydrogel is synergistically constructed via hydrophobic interactions, Diels-Alder dynamic covalent bonds, and Fe 3+ coordination. The hydrogel exhibits comprehensive performance: fracture stress of 1.42 MPa, strain of 718%, toughness of 4.94 MJ/m 3 , Young's modulus of 180.3 kPa, adhesion strength of 23.85 kPa to porcine skin, conductivity of 4.39 S/cm, and high sensitivity (gauge factor = 4.87, pressure sensitivity = 0.92 kPa −1 ). Benefiting from its rapid and stable signal response characteristics, this hydrogel holds significant potential for applications in human motion and subtle physiological signal monitoring. Moreover, the fabricated TENGs exhibit excellent energy harvesting capability. This work reports the design of multifunctional hydrogels featuring balanced mechanical, adhesive, and conductive properties to advance the development of flexible electronics and self-powered devices.

Highly efficient removal of Eu3+ ions using carbon nanotubes-based polymer composites synthesized from the combination of Diels-Alder and multicomponent reactions

Linru Guo,Yanzhu Liu,Jibo Dou,Qiang Huang,Yuan Lei,Junyu Chen,Yuanqing Wen,Yongxiu Li,Xiaoyong Zhang,Yen Wei

The removal of environmental pollutants through adsorption by nanomaterials or nanocomposites has attracted great attention over the past few decades. In this work, a novel strategy that combined with Diels-Alder (DA) and multicomponent reactions has been developed to fabricate carbon nanotubes (CNT) based polymer composites and their potential utilization for removal of rare earth ions from wastewater. First, the amino groups were introduced on the CNT through the DA reaction between CNT and furfurylamine. The obtained amino group-terminating CNT composites (named as CNT-FFA) were further conjugated with the polymers through Kabachnik–Fields (KF) reaction. To evidence the successful fabrication of these CNT based polymer composites, a variety of characterization methods, such as Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS), were used to measure the chemical structure, compositions and thermal stability of CNT based polymer composites. Furthermore, a series of adsorption experiments were implemented to explore the influence of contact time, temperature, initial concentration and pH for adsorption behavior . The results demonstrated that the adsorption capability of resultant CNT based composites (CNT-FFA-PAA) towards Eu 3+ ions is about 130.8 mg g −1 , which is much greater than that of pristine CNT (46.67 mg g −1 ). The above results demonstrated that the method described in this work is a facile and effective tool for fabrication of functional CNT polymer composites, which possess promising prospects for environmental adsorption applications. More importantly, this method in this work could be generally applied in the surface modification of other materials for various applications.

Self-healing waterborne polyurethane/bacterial cellulose composite flexible electronic skin based on Diels-Alder dynamic covalent bonds: Preparation, mechanical properties, and sensing performance

Jin Qian,Xiaoting Hao,Duo Li,Chengshuai Lu,Lulu Chen,Wenjia Han,Zhuqing Liu

High mechanical strength (41.5 MPa) and self-healing efficiency (119%) achieved via DA dynamic covalent bonds and BC reinforcement. • BC-dispersed MWCNTs enable high sensitivity (GF = 10.15) and stable sensing over 0–130% strain. • The flexible electronic skin enables real-time monitoring of joint motions and ECG/EMG signals. Conventional waterborne polyurethane (WPU)-based flexible sensors often exhibit insufficient strength, limited self-healing capacity, and unstable cyclic performance. Herein, a self-healing WPU/bacterial cellulose (BC) composite matrix was fabricated by combining BC nanofiber reinforcement with thermally reversible Diels-Alder (DA) dynamic covalent bonds. Multi-walled carbon nanotubes (MWCNTs) were incorporated as the conductive phase. BC nanofibers interweave with WPU chains to provide topological confinement, while interfacial hydrogen bonding and physical entanglement anchor the polymer chains. At a BC loading of only 5‰, the composite achieved a tensile strength of 41.5 MPa and an elongation at break of 674%. The reversible DA bonds mitigate the trade-off between mechanical strength and self-healing, yielding a self-healing efficiency of 119% after thermal treatment, together with good thermal stability and recyclability. BC also suppresses MWCNT agglomeration and promotes the formation of stable conductive networks. The resulting films exhibited a gauge factor (GF) of 10.15, a stable sensing response over a strain range of 0–130%, and the ability to detect human motion, electromyographic, and electrocardiographic signals. These multifunctional composite films combine mechanical robustness, self-healing performance, and reliable sensing behaviour, indicating their potential for wearable electronics and physiological monitoring. Download: Download high-res image (146KB) Download: Download full-size image

Self-Healing and Flame-Retardant Modifications of Epoxy Resins by the Diels–Alder Release-Delivery Strategy for a High-Efficiency and Green Application

Tingting Lian,Shengchang Zhang,Qibin Xu,Kaixiang Wang,Bo Li,Xiangpu Qin,Mengjin Jiang,Pengqing Liu

The sustainability of epoxy thermosets (EPs) and EP-based composites is always limited by the evolution of internal microcracks and flammability. Herein, inspired by the drug release-delivery system for disease treatment, these symptoms of EP are solved efficiently by a multifunctional Diels–Alder (DA) release-delivery system. First, this novel system is fabricated by the cyclization reaction between the furan diene-containing phosphorus derivative and the maleimide dienophile. The resultant DA system is linked to the epoxy resin by the grafting reaction, thus ensuring its uniform dispersion. Being faced with the formation of inner microcracks, the maleimide dienophiles were released from the DA adducts under the mediated action of temperature and then were delivered to the targeted microcracks under the chemical potential difference derived from the variation of free volume. Then, the released maleimide molecules re-connect with the furan groups that existed near the microcracks to complete the repairing of the EP matrix. The skeletal structure of the EP was well preserved throughout the restoration process. Satisfactory flexural strength (105.5 MPa) and excellent crack-healing efficiency (104.5%) can be obtained for the modified EP. After three constant strain cycles, the stress retention rate can be readily maintained (more than 75%). In addition, due to the phosphorus–nitrogen synergistic flame-retardant effect from the DA system, not only the limited oxygen index of the DA-modified EP matrix can be improved to 27.5% but the lower peak release rate and lower total heat release are also observed compared with the unmodified EP.

Polymerization of an AB-Type Benzoxazine Monomer toward Different Polybenzoxazine Networks: When Diels–Alder Reaction Meets Benzoxazine Chemistry in a Single-Component Resin

Kan Zhang,Yuqi Liu,Hatsuo Ishida

We report a new AB-type benzoxazine monomer, containing both maleimide and furan groups, which exhibits diversified polymerization mechanisms rather than the common single linear polymerization or ring-opening polymerization that leads to cross-linked structures. In addition, the polybenzoxazine obtained directly from the thermally activated polymerization shows higher thermal stability and lower flammability than the one based on the main-chain-type precursor. This is observed as an exception in benzoxazine chemistry because the other reported thermosets derived from main-chain-type benzoxazines generally possess higher performance compared with ones from monomers. More importantly, the varied polymerization mechanisms discovered in this single-component AB-type benzoxazine have cast new light on both benzoxazine chemistry and the Diels–Alder reaction.

Tailor-made PEG-DA-CuS nanoparticles enriched in tumor with the aid of retro Diels–Alder reaction triggered by their intrinsic photothermal property

Jie Sheng,Beibei Ma,Qian Yang,Chao Zhang,Zhongying Jiang,Entomack Borrathybay

A covalently cross-linked reduced functionalized graphene oxide/polyurethane composite based on Diels–Alder chemistry and its potential application in healable flexible electronics

Jinhui Li,Guoping Zhang,Rong Sun,Ching-Ping Wong

A self-healing polymer with excellent mechanical properties, thermal stability, and multiple repairing has attracted increasing interest. However, very few works focused on the self-healing composites and investigated their applications in flexible electronics. Herein, covalently cross-linked reduced functionalized graphene oxide/polyurethane (RFGO/PU) composites based on Diels–Alder (DA) chemistry were developed and applied in healable flexible electronics. GO sheets were modified by furfurylamine followed by reduction resulting in RFGO sheets. Then RFGO was covalently cross-linked with furfuryl-contained linear PU and bismaleimide by DA chemistry. Benefiting from the successful modification of furfuryl, the good dispersion and excellent capability of microwave-to-heat conversion of RFGO, the synthesized composites exhibited not only enhanced mechanical properties and great thermal stability but also excellent electromagnetic wave healable properties. In addition, new composites were employed as the elastic matrix and introduced into the three-dimensional fragmentized graphene foam which served as the conductive path to fabricate flexible electronics. The as-prepared flexible electronics were successfully employed as flexible conductors and strain sensors and were able to detect the biosignals of finger bending. Besides all these, these flexible electronics could be healed efficiently using microwaves in 5 minutes showing great potential in healable flexible electronics.

Peptide nanovaccine conjugated via a retro-Diels–Alder reaction linker for overcoming the obstacle in lymph node penetration and eliciting robust cellular immunity

Kuncheng Lv,Sheng Ma,Liping Liu,Hongyu Chen,Zichao Huang,Zhenyi Zhu,Yibo Qi,Wantong Song

Nanoparticles have been regarded as a promising vaccine adjuvant due to their innate immune potentiation and enhanced antigen transport. However, the inefficient infiltration into the lymph node (LN) paracortex of nanoparticles caused by subcapsular sinus (SCS) obstruction is the main challenge in further improvement of nanovaccine immune efficacy. Herein, we propose to overcome paracortex penetration by using nanovaccine to spontaneously and continuously release antigens after retention in the SCS. In detail, we utilized a spontaneous retro-Diels–Alder (r-D–A) reaction linker to connect poly{(2-methyl-2-oxazoline)80-co-[(2-butyl-2-oxazoline)15-r-(2-thioethyl-2-oxazoline)8]} (PMBOxSH) and peptides for the peptide nanovaccine construction. The r-D–A reaction linker can spontaneously break over time, allowing the nanovaccine to release free antigens and adjuvants upon reaching the LN, thereby facilitating the entry of released antigens and adjuvants into the interior of the LNs. We showed that the efficacy of the peptide nanovaccine constructed using this dynamic linker could be significantly improved, thus greatly enhancing the tumor inhibition efficacy in the B16-OVA model. This dynamic-covalent-chemistry-based vaccine strategy may inspire designing more efficient therapeutic vaccines, especially those that require eliciting high-amount T cell responses.

Recyclable and removable functionalization based on Diels-Alder reaction of black phosphorous nanosheets and its dehydration carbonization in fire safety improvement of polymer composites

Wei Cai,Zhaoxin Li,Jiajia Liu,Shuilai Qiu,Ying Pan,Zhoumei Xu,Chao Ma,Yuan Hu

Based on reversible Diels-Alder reaction, we herein precisely control the formation and elimination of surface functionalization composed of triallyl isocyanurate for black phosphorous (BP) nanosheets, at different reaction temperatures. Direct TEM observation, FTIR spectra, and XPS test confirm that this surface functionalization is capable of firstly covering onto the surface of BP nanosheets and then removed. This surface functionalization not only improves the interfacial interaction between BP nanosheets and polymer matrix, but also converts BP nanosheets into phosphorus pentoxide and phosphoric acid owning dehydration carbonization effect. As a result, cone calorimetric test demonstrates that incorporating 2.0 wt% functionalized BP nanosheets strikingly decreases the peak heat release rate (PHRR) and total heat release (THR) of thermoplastic polyurethane (TPU) by 61.6% and 56.7%, respectively. Such a novel strategy simultaneously improves the flame retardancy, solves the contradiction between high crystal purity and surface functionalization, and offers recycle capsulation method for BP nanosheets.

Direct generation of poly(ionic liquids) on mesoporous carbon via Diels–Alder and multicomponent reactions for ultrafast adsorptive removal anionic organic dye with high efficiency

Fengjie Deng,Jie Liang,Guang Yang,Qiang Huang,Jibo Dou,Junyu Chen,Yuanqing Wen,Meiying Liu,Xiaoyong Zhang,Yen Wei

The porous materials have been extensively explored for various applications especially for the environmental treatment. In this work, we reported a novel strategy for the surface modification of mesoporous carbon (MC) that relied on an efficient and green Diels–Alder [4 + 2] cycloaddition and the multicomponent Radziszewski reactions for the first time to in-situ generate poly (ionic liquids) (PIL) on the surface of MC. The resulting MC@PIL composites have been characterized using a series of instrumental techniques to elucidate their morphology, chemical compositions and other properties. Batch experiments towards adsorbing Congo red (CR) with contact time, initial concentration, variable pH and reaction system temperature were conducted to evaluate the adsorption behaviors. Furthermore, thermodynamic analysis of adsorption process is also discussed. The results demonstrated that CR could be rapidly adsorbed on MC-PIL composites within 10 min and displayed obvious enhancement adsorption capacity (331.49 mg/g) towards CR as compared with pristine MC. In addition, the adsorption/desorption cycle of the MC@PIL composites was also tested. The results show that the adsorption capacity of the third adsorption-desorption cycle can reach 199.0223 mg/g and desorption yield above 80%. Considered the good designability of molecules involved in Radziszewski reaction, many functionalized MC could thus be fabricated and these PIL functionalized composites should be efficient and promising candidates for removal of different pollutants from wastewater.

Minimally invasive delivery of human umbilical cord-derived mesenchymal stem cells by an injectable hydrogel via Diels–Alder click reaction for the treatment of intrauterine adhesions

Sentao Hu,Yangyang Dai,Liaobing Xin,Xiaowen Zheng,Zi Ye,Songying Zhang,Lie Ma

Intrauterine adhesions (IUA) are the most common cause of uterine infertility, and conventional treatments have not consistently achieved satisfactory pregnancy rates. Stem cell therapy shows promising potential for the clinical treatment of IUA. Although various advanced biomaterials have been designed for delivering stem cells to the uterine cavity, there remain significant challenges, particularly in devising therapeutic strategies for clinical application that minimize surgical incisions and conform to the intricate structure of uterine cavity. Herein, an injectable hydrogel loaded with human umbilical cord-derived mesenchymal stem cells (UCMSCs) was synthesized via the Diels-Alder click reaction for endometrial regeneration and fertility restoration, exhibiting suitable mechanical properties, good biocompatibility, and desirable degradation properties. Notably, this hydrogel permitted minimally invasive administration and integrated seamlessly with surrounding tissue. Our study revealed that the UCMSCs-laden injectable hydrogel enhanced cell proliferation, migration, angiogenesis, and exhibited anti-fibrotic effects in vitro. The implantation of this hydrogel significantly facilitated endometrium regeneration and restored fertility in a rat endometrial damage model. Mechanistically, in vivo results indicated that the UCMSCs-laden injectable hydrogel effectively promoted macrophage recruitment and facilitated M2 phenotype polarization. Collectively, this hydrogel demonstrated efficacy in regenerating damaged endometrium, leading to the restoration of fertility. Consequently, it holds promise as a potential therapeutic strategy for endometrial damage and fertility decline arising from intrauterine adhesions. Statement of significance Severe endometrial traumas frequently lead to intrauterine adhesions and subsequent infertility. Stem cell therapy shows promising potential for the clinical treatment of IUA; however, challenges remain, including low delivery efficiency and compromised stem cell activity during the delivery process. In this study, we fabricated an injectable hydrogel loaded with UCMSCs via the Diels-Alder click reaction, which exhibited unique bioorthogonality. The in situ-gelling hydrogels could be introduced through a minimally invasive procedure and adapt to the intricate anatomy of the uterus. The UCMSCs-laden injectable hydrogel promoted endometrial regeneration and fertility restoration in a rat endometrial damage model, efficaciously augmenting macrophage recruitment and promoting their polarization to the M2 phenotype. The administration of UCMSCs-laden injectable hydrogel presents a promising therapeutic strategy for patients with severe intrauterine adhesion.

Fabrication of well-defined lignin-derived elastomers by atom transfer radical polymerization and Diels-Alder reaction towards sustainable, super-tough and high temperature-resistant hot-melt adhesives

Tong Luo,Chuanwei Lu,Ji Qi,Chunpeng Wang,Fuxiang Chu,Jifu Wang

Hot-melt adhesives synthesized from sustainable resource have attracted increasing attention in fields of home decoration, handicraft production, automotive industries, etc., due to their free of volatile organic compounds (VOCs) and environmentally friendly advantages. However, it is still challenging to fabricate super-tough and heat-resistant hot-melt adhesives with utilization of the inherited properties of sustainable resource as feedstock. Herein, a combination of photoinduced metal-free atom transfer radical polymerization (ATRP) and Diels-Alder (DA) reaction was applied to prepare lignin-derived elastomers for super-tough and high temperature-resistant hot-melt adhesives. Firstly, photoinduced metal-free ATRP of lauryl methacrylate (LMA) derived from fatty acids and furfuryl methacrylate (FMA) derived from furfural, were employed to fabricate sustainable well-defined multi-arm lignin-graft copolymers bearing furfuryl groups with the aid of lignin based macro-initiator (L-Br). The photoinduced metal-free ATRP in this work could be activated and deactivated by an “ON–OFF” ultraviolet (UV) light switch, and successfully achieved the precise control over the molecular weight and composition of lignin-graft copolymers. Then, Diels-Alder (DA) reaction was applied to functionalize the lignin-graft copolymers with dynamic crosslinked network and obtain the lignin-derived elastomers. Benefiting from the multi-arm structure and the dynamic crosslinked network, these lignin-derived elastomers exhibited favorable mechanical property, thermal stability, shape memory, self-healing and recycled properties. In addition, the lignin-derived elastomers could be used as hot-melt adhesives and their lap shear strengths could reach 5.95 MPa, while being bonded with aluminum plates. Moreover, the steel plate bonded with lignin-derived elastomers could remain stable even at 100 °C. We believe that this work will offer a new approach for designing lignin-derived elastomers towards sustainable, strong, super-tough and high-temperature-resistant hot-melt adhesives.