Dual stimuli responsive self-healing and malleable materials based on dynamic thiol-Michael chemistry

2017 ◽  
Vol 8 (42) ◽  
pp. 6534-6543 ◽  
Author(s):  
Progyateg Chakma ◽  
Luiz Henrique Rodrigues Possarle ◽  
Zachary A. Digby ◽  
Borui Zhang ◽  
Jessica L. Sparks ◽  
...  

Thiol-maleimide adducts are incorporated as crosslinkers into polymer networks and act as pH-responsive and thermoresponsive dynamic crosslinkers, imparting malleability and self-healing properties into the material.

2020 ◽  
Vol 2 (2) ◽  
pp. 38

The Diels-Alder reaction between furan and maleimide is the most studied example of reversible covalent chemistries for creating self-healing materials. While scientific articles reporting the synthesis of new reversible polymer networks are numerous, accurate knowledge of the reaction kinetics and thermodynamics of the dynamically reversible equilibrium reaction and the structure and property development of derived stimuli-responsive materials are less widespread. The requirements for the material properties and behavior become more stringent when designing materials for dedicated applications, such as soft robotic structures. Optima need to be sought between reasonably fast reaction kinetics for fast and efficient damage healing at moderate temperatures and mechanical strength and structural stability on the other hand. Stress relaxation is desired to make materials tougher, relieving stress before defects can grow into cracks and ultimately lead to failure, while creep can’t be allowed. Recycling and reprocessing of materials are desirable from an ecological viewpoint, while the materials should also be able to withstand static and dynamic loading in a considerable range of environmental conditions. Accurate knowledge of the reaction kinetics and thermodynamics and an in-depth knowledge of structure-processing-property relations allow smart polymer network design with tailored stimuli-responsive behavior and use as self-healing materials for robotic applications.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiahui He ◽  
Zixi Zhang ◽  
Yutong Yang ◽  
Fenggang Ren ◽  
Jipeng Li ◽  
...  

AbstractEndoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are well-established therapeutics for gastrointestinal neoplasias, but complications after EMR/ESD, including bleeding and perforation, result in additional treatment morbidity and even threaten the lives of patients. Thus, designing biomaterials to treat gastric bleeding and wound healing after endoscopic treatment is highly desired and remains a challenge. Herein, a series of injectable pH-responsive self-healing adhesive hydrogels based on acryloyl-6-aminocaproic acid (AA) and AA-g-N-hydroxysuccinimide (AA-NHS) were developed, and their great potential as endoscopic sprayable bioadhesive materials to efficiently stop hemorrhage and promote the wound healing process was further demonstrated in a swine gastric hemorrhage/wound model. The hydrogels showed a suitable gelation time, an autonomous and efficient self-healing capacity, hemostatic properties, and good biocompatibility. With the introduction of AA-NHS as a micro-cross-linker, the hydrogels exhibited enhanced adhesive strength. A swine gastric hemorrhage in vivo model demonstrated that the hydrogels showed good hemostatic performance by stopping acute arterial bleeding and preventing delayed bleeding. A gastric wound model indicated that the hydrogels showed excellent treatment effects with significantly enhanced wound healing with type I collagen deposition, α-SMA expression, and blood vessel formation. These injectable self-healing adhesive hydrogels exhibited great potential to treat gastric wounds after endoscopic treatment.


2019 ◽  
Vol 6 (1) ◽  
pp. 160-168 ◽  
Author(s):  
Yajuan Sun ◽  
Linfeng Chen ◽  
Yan Jiang ◽  
Xuan Zhang ◽  
Xiukai Yao ◽  
...  

A general class of stimuli-responsive grippers and actuators (e.g., temperature- and pH-responsive) with surprisingly high gripping strengths is introduced.


2017 ◽  
Vol 8 (2) ◽  
pp. 1350-1355 ◽  
Author(s):  
Alexander S. Groombridge ◽  
Aniello Palma ◽  
Richard M. Parker ◽  
Chris Abell ◽  
Oren A. Scherman

The successful self-assembly of a stimuli-responsive aqueous supramolecular hyperbranched polymer from small molecules and the macrocyclic host cucurbit[8]uril (CB[8]) is reported. This self-healing supramolecular network can act as a soft matter barrier at liquid–liquid interfaces.


Soft Matter ◽  
2021 ◽  
Author(s):  
Marcelo Ricardo Romero ◽  
Gisella Trejo ◽  
José Vedelago ◽  
Cesar Gomez

A chemical actuator was developed taking advantage of the internal microstructure of a plant stem. Stem xylems of Cucurbita moschata were chemically modified with a pH-responsive polymer to obtain an...


Soft Matter ◽  
2019 ◽  
Vol 15 (36) ◽  
pp. 7117-7121 ◽  
Author(s):  
Dennis Aschmann ◽  
Steffen Riebe ◽  
Thorben Neumann ◽  
Dennis Killa ◽  
Jan-Erik Ostwaldt ◽  
...  

A dual pH-responsive two component hydrogelator with aggregation-induced emission properties is described. The orchestration of supramolecular guadiniumcarbonylpyrrole dimerisation and the recognition of carboxylic acid is reason for the gelation.


Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2051
Author(s):  
Anju Maria Thomas ◽  
Jerome Peter ◽  
Saravanan Nagappan ◽  
Anandhu Mohan ◽  
Chang-Sik Ha

In the present work, a temperature and pH-responsive hybrid catalytic system using copolymer-capped mesoporous silica particles with metal nanoparticles is proposed. The poly(2-(dimethylamino)ethyl methacrylate)(DMAEMA)-co-N-tert-butyl acrylamide) (TBA)) shell on mesoporous silica SBA-15 was obtained through free radical polymerization. Then, copper nanoparticles (CuNPs) decorated SBA-15/copolymer hybrid materials were synthesized using the NaBH4 reduction method. SBA-15 was functionalized with trimethoxylsilylpropyl methacrylate (TMSPM) and named TSBA. It was found that the CuNPs were uniformly dispersed in the mesoporous channels of SBA-15, and the hybrid catalyst exhibited excellent catalytic performance for the selective oxidation of different substituted benzyl alcohols in water using H2O2 as an oxidant at room temperature. The dual (temperature and pH-) responsive behaviors of the CuNPs/p(DMAEMA-co-TBA)/TSBA catalyst were investigated using the dynamic light scattering technique. The conversion of catalytic products and selectivity were calculated using gas chromatographic techniques, whereas the molecular structure of the products was identified using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The catalyst showed excellent catalytic activity toward the oxidation of alcohol to aldehyde in an aqueous medium below the lower critical solution temperature (LCST) and pKa values (7–7.5) of the copolymer. The main advantages of the hybrid catalyst, as compared to the existing catalysts, are outstanding alcohol conversion (up to 99%) for a short reaction time (1 h), small amount of the catalyst (5 mg), and good recyclability equal to at least five times.


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