Recycling and self-healing of dynamic covalent polymer networks with a precisely tuneable crosslinking degree

2019 ◽  
Vol 10 (6) ◽  
pp. 672-678 ◽  
Author(s):  
Qi An ◽  
Isabelle D. Wessely ◽  
Yannick Matt ◽  
Zahid Hassan ◽  
Stefan Bräse ◽  
...  
Keyword(s):  
Polymer Networks ◽  
Self Healing ◽  
Crosslinking Degree ◽  
Covalent Bonds ◽  
External Stimuli

Dynamic covalent polymer networks combine intrinsic reversibility with the robustness of covalent bonds, creating chemically stable materials that are responsive to external stimuli.

Catalyst-Free Room-Temperature Self-Healing Polymer Networks Based on Dynamic Covalent Quinone Methide-Secondary Amine Chemistry

2021 ◽  
Author(s):  
Yuanxing Zhang ◽  
Ying Wu ◽  
Jiayi Li ◽  
Ke Zhang
Keyword(s):  
Secondary Amine ◽  
Michael Addition ◽  
Room Temperature ◽  
Polymer Networks ◽  
Quinone Methide ◽  
Self Healing ◽  
Ambient Conditions ◽  
Catalyst Free ◽  
External Stimuli

An aza-Michael addition between 2,6-di-t-butyl-7-phenyl-p-quinone methide and secondary amine was demonstrated to hold the dynamic covalent reaction property under ambient conditions requiring no external stimuli. Based on this dynamic covalent...

scholarly journals Dually Crosslinked Polymer Networks Incorporating Dynamic Covalent Bonds

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 396
Author(s):  
Larissa Hammer ◽  
Nathan J. Van Zee ◽  
Renaud Nicolaÿ
Keyword(s):  
Physical Properties ◽  
Dimensional Stability ◽  
Dynamic Networks ◽  
Polymer Networks ◽  
Polymeric Materials ◽  
Self Healing ◽  
Structure Property ◽  
Covalent Bonds ◽  
Design Structure ◽  
Increasing Demand

Covalent adaptable networks (CANs) are polymeric networks containing covalent crosslinks that are dynamic under specific conditions. In addition to possessing the malleability of thermoplastics and the dimensional stability of thermosets, CANs exhibit a unique combination of physical properties, including adaptability, self-healing, shape-memory, stimuli-responsiveness, and enhanced recyclability. The physical properties and the service conditions (such as temperature, pH, and humidity) of CANs are defined by the nature of their constituent dynamic covalent bonds (DCBs). In response to the increasing demand for more sophisticated and adaptable materials, the scientific community has identified dual dynamic networks (DDNs) as a promising new class of polymeric materials. By combining two (or more) distinct crosslinkers in one system, a material with tailored thermal, rheological, and mechanical properties can be designed. One remarkable ability of DDNs is their capacity to combine dimensional stability, bond dynamicity, and multi-responsiveness. This review aims to give an overview of the advances in the emerging field of DDNs with a special emphasis on their design, structure-property relationships, and applications. This review illustrates how DDNs offer many prospects that single (dynamic) networks cannot provide and highlights the challenges associated with their synthesis and characterization.

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 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.

Topological liquid crystal superstructures as structured light lasers

2021 ◽  
Vol 118 (49) ◽  
pp. e2110839118
Author(s):  
Miha Papič ◽  
Urban Mur ◽  
Kottoli Poyil Zuhail ◽  
Miha Ravnik ◽  
Igor Muševič ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Matter ◽  
Structured Light ◽  
Topological Defects ◽  
Photonic Devices ◽  
Light Polarization ◽  
Self Healing ◽  
Fabry Perot ◽  
Self Assembled ◽  
External Stimuli

Liquid crystals (LCs) form an extremely rich range of self-assembled topological structures with artificially or naturally created topological defects. Some of the main applications of LCs are various optical and photonic devices, where compared to their solid-state counterparts, soft photonic systems are fundamentally different in terms of unique properties such as self-assembly, self-healing, large tunability, sensitivity to external stimuli, and biocompatibility. Here we show that complex tunable microlasers emitting structured light can be generated from self-assembled topological LC superstructures containing topological defects inserted into a thin Fabry–Pérot microcavity. The topology and geometry of the LC superstructure determine the structuring of the emitted light by providing complex three-dimensionally varying optical axis and order parameter singularities, also affecting the topology of the light polarization. The microlaser can be switched between modes by an electric field, and its wavelength can be tuned with temperature. The proposed soft matter microlaser approach opens directions in soft matter photonics research, where structured light with specifically tailored intensity and polarization fields could be designed and implemented.

scholarly journals Reversible Assembly of Terpyridine Incorporated Norbornene-Based Polymer via a Ring-Opening Metathesis Polymerization and Its Self-Healing Property

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1173 ◽  
Author(s):  
Jookyeong Lee ◽  
Hwi Moon ◽  
Keewook Paeng ◽  
Changsik Song
Keyword(s):  
Ring Opening ◽  
Transition Metal Ions ◽  
Self Healing ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Ligand Interactions ◽  
Healing Agent ◽  
Healing Property ◽  
External Stimuli ◽  
Metal Ligand

We induced a terpyridine moiety into a norbornene-based polymer to demonstrate its self-healing property, without an external stimulus, such as light, heat, or healing agent, using metal–ligand interactions. We synthesized terpyridine incorporated norbornene-based polymers using a ring-opening metathesis polymerization. The sol state of diluted polymer solutions was converted into supramolecular assembled gels, through the addition of transition metal ions (Ni2+, Co2+, Fe2+, and Zn2+). In particular, a supramolecular complex gel with Zn2+, which is a metal with a lower binding affinity, demonstrated fast self-healing properties, without any additional external stimuli, and its mechanical properties were completely recovered.

A self-healing and multi-responsive hydrogel based on biodegradable ferrocene-modified chitosan

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55133-55138 ◽  
Author(s):  
Ya-Kun Li ◽  
Cheng-Gong Guo ◽  
Liang Wang ◽  
Youqian Xu ◽  
Chen-yang Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
The Self ◽  
Self Healing ◽  
Modified Chitosan ◽  
Acid Aqueous Solution ◽  
External Stimuli

Here, we present a novel and facile method for constructing a self-healing hydrogel with multi-responses to external stimuli via the self-assemble of biodegradable ferrocene-modified chitosan (FcCS) in an acid aqueous solution.

Self-Healing Polymers Based on Reversible Covalent Bonds

2015 ◽  
pp. 1-58 ◽  
Author(s):  
Natascha Kuhl ◽  
Stefan Bode ◽  
Martin D. Hager ◽  
Ulrich S. Schubert
Keyword(s):  
Self Healing ◽  
Covalent Bonds ◽  
Reversible Covalent

scholarly journals Room-temperature autonomous self-healing glassy polymers with hyperbranched structure

2020 ◽  
Vol 117 (21) ◽  
pp. 11299-11305 ◽  
Author(s):  
Hao Wang ◽  
Hanchao Liu ◽  
Zhenxing Cao ◽  
Weihang Li ◽  
Xin Huang ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Room Temperature ◽  
Glassy State ◽  
Glassy Polymers ◽  
Self Healing ◽  
External Branch ◽  
Healing Efficiency ◽  
High Degree ◽  
External Stimuli ◽  
Hyperbranched Structure

Glassy polymers are extremely difficult to self-heal below their glass transition temperature (Tg) due to the frozen molecules. Here, we fabricate a series of randomly hyperbranched polymers (RHP) with high density of multiple hydrogen bonds, which showTgup to 49 °C and storage modulus up to 2.7 GPa. We reveal that the hyperbranched structure not only allows the external branch units and terminals of the molecules to have a high degree of mobility in the glassy state, but also leads to the coexistence of “free” and associated complementary moieties of hydrogen bonds. The free complementary moieties can exchange with the associated hydrogen bonds, enabling network reconfiguration in the glassy polymer. As a result, the RHP shows amazing instantaneous self-healing with recovered tensile strength up to 5.5 MPa within 1 min, and the self-healing efficiency increases with contacting time at room temperature without the intervention of external stimuli.

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