Transparent, robust, water-resistant and high-barrier self-healing elastomers reinforced with dynamic supramolecular nanosheets with switchable interfacial connections

2020 ◽  
Vol 8 (18) ◽  
pp. 9013-9020 ◽  
Author(s):  
Haitao Wei ◽  
Yi Yang ◽  
Xin Huang ◽  
Yong Zhu ◽  
Hao Wang ◽  
...  
Keyword(s):  
Self Healing ◽  
Covalent Bonds ◽  
Bottom Up

A bottom-up strategy to reinforce self-healing elastomers with in situ assembled supramolecular nanosheets with switchable interfacial covalent bonds.

scholarly journals Polysaccharide-Based In Situ Self-Healing Hydrogels for Tissue Engineering Applications

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2261
Author(s):  
Sheila Maiz-Fernández ◽  
Leyre Pérez-Álvarez ◽  
Leire Ruiz-Rubio ◽  
Jose Luis Vilas-Vilela ◽  
Senentxu Lanceros-Mendez
Keyword(s):  
Tissue Engineering ◽  
Personalized Medicine ◽  
Tissue Regeneration ◽  
Self Healing ◽  
Covalent Bonds ◽  
Surgical Interventions ◽  
Non Invasive ◽  
Potential Applications ◽  
Physical Interactions

In situ hydrogels have attracted increasing interest in recent years due to the need to develop effective and practical implantable platforms. Traditional hydrogels require surgical interventions to be implanted and are far from providing personalized medicine applications. However, in situ hydrogels offer a wide variety of advantages, such as a non-invasive nature due to their localized action or the ability to perfectly adapt to the place to be replaced regardless the size, shape or irregularities. In recent years, research has particularly focused on in situ hydrogels based on natural polysaccharides due to their promising properties such as biocompatibility, biodegradability and their ability to self-repair. This last property inspired in nature gives them the possibility of maintaining their integrity even after damage, owing to specific physical interactions or dynamic covalent bonds that provide reversible linkages. In this review, the different self-healing mechanisms, as well as the latest research on in situ self-healing hydrogels, is presented, together with the potential applications of these materials in tissue regeneration.

Imine Based Self-Healing Hydrogel Triggered by Periodate

2020 ◽  
Author(s):  
Alexis Wolfel ◽  
Cecilia Inés Alvarez Igarzabal ◽  
Marcelo Ricardo Romero
Keyword(s):  
Functional Groups ◽  
Time Window ◽  
Crosslinking Reaction ◽  
Self Healing ◽  
Swelling Properties ◽  
Covalent Bonds ◽  
Smart Systems ◽  
Primary Amino ◽  
Vicinal Diols ◽  
Aldehyde Groups

<p>Design of materials with novel sensitivities and smart behaviour is important for the development of smart systems with automated responsiveness. We have recently reported the synthesis of hydrogels, cross-linked by <i>N,N'</i>-diallyltartardiamide (DAT). The covalent DAT-crosslinking points have vicinal diols which can be easily cleaved with periodate, generating valuable a-oxo-aldehyde functional groups, useful for further chemical modification. Based on those findings, we envisioned that a self-healable hydrogel could be obtained by incorporation of primary amino functional groups, from <a>2-aminoethyl methacrylate </a>hydrochloride (AEMA), coexisting with DAT into the same network. The a-oxo-aldehyde groups generated after the reaction with periodate would arise in the immediate environment of amine groups to form imine cross-links. For this purpose, DAT-crosslinked hydrogels were synthesized and carefully characterized. The cleavage of DAT-crosslinks with periodate promoted changes in the mechanical and swelling properties of the materials. As expected, a self-healing behavior was observed, based on the spontaneous formation of imine covalent bonds. In addition, we surprisingly found a combination of fast vicinal diols cleavage and a low speed self-crosslinking reaction by imine formation. Consequently, it was found a time-window in which a periodate-treated polymer was obtained in a transient liquid state, which can be exploited to choose the final shape of the material, before automated gelling. The singular properties attained on these hydrogels could be useful for developing sensors, actuators, among other smart systems.</p>

scholarly journals Cell-free protein synthesis and in situ immobilization of deGFP-MatB in polymer microgels for malonate-to-malonyl CoA conversion

RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 40588-40596
Author(s):  
Tony Köhler ◽  
Thomas Heida ◽  
Sandra Hoefgen ◽  
Niclas Weigel ◽  
Vito Valiante ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Genetic Information ◽  
In Situ Immobilization ◽  
Bottom Up ◽  
Free Protein ◽  
Malonyl Coa ◽  
Cell Free Protein Synthesis

We describe a bottom-up approach towards functional enzymes utilizing microgels as carriers for genetic information that enable cell-free protein synthesis, in situ immobilization, and utilization of functional deGFP-MatB.

Recyclable conductive nanoclay for direct in situ printing flexible electronics

2021 ◽  
Author(s):  
Pengcheng Wu ◽  
Zhenwei Wang ◽  
Xinhua Yao ◽  
Jianzhong Fu ◽  
Yong He
Keyword(s):  
Flexible Electronics ◽  
Self Healing ◽  
Stamping Process

A recyclable, self-healing conductive nanoclay and corresponding stamping process are developed for printing flexible electronics directly and quickly in situ.

scholarly journals Biohydrogel Based on Dynamic Covalent Bonds for Wound Healing Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6945
Author(s):  
Chukwuma O. Agubata ◽  
Cynthia C. Mbaoji ◽  
Ifeanyi T. Nzekwe ◽  
César Saldías ◽  
David Díaz Díaz
Keyword(s):  
Wound Healing ◽  
Interfacial Tension ◽  
Blood Clotting ◽  
Phenylboronic Acid ◽  
Moisture Loss ◽  
Self Healing ◽  
Covalent Bonds ◽  
Treatment Groups ◽  
Acid Soluble Collagen ◽  
Thixotropic Behavior

In this work, a biohydrogel based on alginate and dynamic covalent B-O bonds, and derived composites, has been evaluated for wound healing applications. In particular, a phenylboronic acid–alginate (PBA-Alg) complex was synthesized by coupling 3-aminophenylboronic acid onto alginate, and used to prepare varied concentrations of hydrogels and silicate-based nanocomposites in PBS. The resulting hydrogels were characterized in terms of interfacial tension, moisture uptake and loss, interaction with fresh acid-soluble collagen, self-healing ability, effects on blood clotting and wound healing. The interfacial tension between the hydrogels and biorelevant fluids was low and moisture loss of 55%–60% was evident without uptake from the environment. The components of the hydrogels and their mixtures with collagen were found to be compatible. These hydrogels showed efficient self-healing and thixotropic behavior, and the animals in the treatment groups displayed blood clotting times between 9.1 min and 10.7 min. In contrast, the composites showed much longer or shorter clotting times depending on the silicate content. A significant improvement in wound healing was observed in 3% w/v PBA-Alg formulations. Overall, the PBA-Alg hydrogels exhibit self-healing dynamic covalent interactions and may be useful in dressings for incision wounds.

SELF-HEALING OF WOVEN COMPOSITE LAMINATES VIA IN SITU THERMAL REMENDING

2021 ◽  
Author(s):  
ALEXANDER D. SNYDER ◽  
ZACHARY J. PHILLIPS ◽  
JASON F. PATRICK
Keyword(s):  
Composite Laminates ◽  
Composite Laminate ◽  
Laminated Composites ◽  
Reaction Times ◽  
Carbon Fiber Composites ◽  
Self Healing ◽  
Damage Mode ◽  
Woven Composite ◽  
Internal Damage

Fiber-reinforced polymer composites are attractive structural materials due to their high specific strength/stiffness and excellent corrosion resistance. However, the lack of through-thickness reinforcement in laminated composites creates inherent susceptibility to fiber-matrix debonding, i.e., interlaminar delamination. This internal damage mode has proven difficult to detect and nearly impossible to repair via conventional methods, and therefore, remains a significant factor limiting the reliability of composite laminates in lightweight structures. Thus, novel approaches for mitigation (e.g., self-healing) of this incessant damage mode are of tremendous interest. Self-healing strategies involving sequestration of reactive liquids, i.e. microcapsule and microvascular systems, show promise for the extending service- life of laminated composites. However, limited heal cycles, long reaction times (hours/days), and variable stability of chemical agents under changing environmental conditions remain formidable research challenges. Intrinsic self- healing approaches that utilize reversible bonds in the host material circumvent many of these limitations and offer the potential for unlimited heal cycles. Here we detail the development of an intrinsic self-healing woven composite laminate based on thermally-induced dynamic bond re-association of 3D-printed polymer interlayers. In contrast to prior work, self-repair of the laminate occurs in situ and below the glass-transition temperature of the epoxy matrix, and maintains >85% of the elastic modulus during healing. This new platform has been deployed in both glass and carbon-fiber composites, demonstrating application versatility. Remarkably, up to 20 rapid (minute-scale) self-healing cycles have been achieved with healing efficiencies hovering 100% of the interlayer toughened (4-5x) composite laminate. This latest self-healing advancement exhibits unprecedented potential for perpetual in-service repair along with material multi-functionality (e.g., deicing ability) to meet modern application demands.

scholarly journals Microencapsulation of Liquid Cyanoacrylate via In Situ Polymerization for Self-healing Bone Cement Application – ERRATUM

2012 ◽  
Vol 1417 ◽  
pp. 1-13
Author(s):  
Vineela D. Gandham ◽  
Alice B.W. Brochu ◽  
William M. Reichert
Keyword(s):  
Bone Cement ◽  
In Situ Polymerization ◽  
Self Healing ◽  
Healing Bone

scholarly journals Soot removal from ancient Egyptian complex painted surfaces using a double network gel: Empirical tests on the ceiling of the sanctuary of Osiris in the temple of Seti I – Abydos

2020 ◽  
Author(s):  
Ehab Awad Al-Emam ◽  
Abdel Ghafour Motawea ◽  
Joost Caen ◽  
Koen Janssens
Keyword(s):  
Self Healing ◽  
Wall Paintings ◽  
Shape Stability ◽  
Double Network ◽  
Ancient Egyptian ◽  
Third Phase ◽  
Digital Microscope ◽  
Seti I ◽  
The Temple

Abstract In this study, we evaluated the ease of removal of soot layers from ancient wall paintings by employing double network gels as a controllable cleaning method. The ceiling of the temple of Seti I (Abydos, Egypt) is covered with thick layers of soot; this is especially the case in the sanctuary of Osiris. These layers may have been accumulated during the occupation of the temple by Christians, fleeing the Romans in the first centuries A.D.. Soot particulates are one of the most common deposits to be removed during conservation-restoration activities of (Egyptian) wall paintings. They usually mask the painted reliefs and reduce the permeability of the painted surface. A Polyvinyl alcohol-borax/agarose (PVA-B/AG) double network gel was selected for this task since its properties were expected to be compatible with the cleaning treatment requirements. The gel is characterized by its flexibility, permitting to take the shape of the reliefs, while also having self-healing properties, featuring shape stability and an appropriate capacity to retain liquid. The gel was loaded with several cleaning reagents that proved to be effective for soot removal. Two sets of soot removal tests were conducted with these gel composites. The cleaned surfaces were examined in situ with the naked eye and with a digital microscope in order to select the best gel composite. The gel composite, loaded with a solution of 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA yielded the most satisfactory results and allowed to safely remove a crust of thick soot particles from the surface. Thus, during a third phase of the study, it was used successfully to clean a larger area of the ceiling.

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