Quantifying the effects of cooperative hydrogen bonds between vicinal diols on polymer dynamics

Thermoreversible rubbers are prepared by the thiol-ene functionalized polybutadiene oligomers via dynamic ionic hydrogen bonds and covalent cross-links, exhibiting tailored properties for self-healing and shape memory functions.

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Imine Based Self-Healing Hydrogel Triggered by Periodate

10.26434/chemrxiv.12592322 ◽

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>

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Self-healing, pH-sensitive and shape memory hydrogels based on acylhydrazone and hydrogen bonds

European Polymer Journal ◽

10.1016/j.eurpolymj.2021.110838 ◽

2021 ◽

pp. 110838

Author(s):

Liyuan Qiao ◽

Chengde Liu ◽

Cheng Liu ◽

Lishuai Zong ◽

Hongjian Gu ◽

...

Keyword(s):

Hydrogen Bonds ◽

Shape Memory ◽

Ph Sensitive ◽

Self Healing

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Irreversible and Self-Healing Electrically Conductive Hydrogels Made of Bio-Based Polymers

International Journal of Molecular Sciences ◽

10.3390/ijms23020842 ◽

2022 ◽

Vol 23 (2) ◽

pp. 842

Author(s):

Ahmed Ali Nada ◽

Anita Eckstein Andicsová ◽

Jaroslav Mosnáček

Keyword(s):

Renewable Resources ◽

Mechanical Stability ◽

Conductive Polymers ◽

Special Focus ◽

Self Healing ◽

Natural Polymers ◽

Electrically Conductive ◽

Preparation Methods ◽

Cross Links ◽

Conductive Hydrogels

Electrically conductive materials that are fabricated based on natural polymers have seen significant interest in numerous applications, especially when advanced properties such as self-healing are introduced. In this article review, the hydrogels that are based on natural polymers containing electrically conductive medium were covered, while both irreversible and reversible cross-links are presented. Among the conductive media, a special focus was put on conductive polymers, such as polyaniline, polypyrrole, polyacetylene, and polythiophenes, which can be potentially synthesized from renewable resources. Preparation methods of the conductive irreversible hydrogels that are based on these conductive polymers were reported observing their electrical conductivity values by Siemens per centimeter (S/cm). Additionally, the self-healing systems that were already applied or applicable in electrically conductive hydrogels that are based on natural polymers were presented and classified based on non-covalent or covalent cross-links. The real-time healing, mechanical stability, and electrically conductive values were highlighted.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2000001117 ◽

2020 ◽

Vol 117 (21) ◽

pp. 11299-11305 ◽

Cited By ~ 6

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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A supramolecular silicone dielectric elastomer with a high dielectric constant and fast and highly efficient self-healing under mild conditions

Journal of Materials Chemistry A ◽

10.1039/d0ta06577c ◽

2020 ◽

Vol 8 (44) ◽

pp. 23330-23343

Author(s):

Haibin Sun ◽

Xueying Liu ◽

Suting Liu ◽

Bing Yu ◽

Nanying Ning ◽

...

Keyword(s):

Dielectric Constant ◽

Hydrogen Bonds ◽

High Dielectric Constant ◽

Dielectric Elastomer ◽

Supramolecular Network ◽

Self Healing ◽

Mild Conditions ◽

Highly Efficient ◽

Coordination Bonds ◽

High Dielectric

A silicone dielectric elastomer with simultaneous high dielectric constant, fast and efficient self-healing ability at mild conditions was prepared by constructing supramolecular network assembled by coordination bonds and hydrogen bonds.

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A Robust, Tough and Multifunctional Polyurethane/Tannic Acid Hydrogel Fabricated by Physical-Chemical Dual Crosslinking

Polymers ◽

10.3390/polym12010239 ◽

2020 ◽

Vol 12 (1) ◽

pp. 239 ◽

Cited By ~ 1

Author(s):

Jie Wen ◽

Xiaopeng Zhang ◽

Mingwang Pan ◽

Jinfeng Yuan ◽

Zhanyu Jia ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Polyethylene Glycol ◽

Hydrogen Bonds ◽

Tannic Acid ◽

Hydroxyl Groups ◽

Self Healing ◽

Physical Chemical ◽

Biomedical Field ◽

Physical Crosslinking

Commonly synthetic polyethylene glycol polyurethane (PEG–PU) hydrogels possess poor mechanical properties, such as robustness and toughness, which limits their load-bearing application. Hence, it remains a challenge to prepare PEG–PU hydrogels with excellent mechanical properties. Herein, a novel double-crosslinked (DC) PEG–PU hydrogel was fabricated by combining chemical with physical crosslinking, where trimethylolpropane (TMP) was used as the first chemical crosslinker and polyphenol compound tannic acid (TA) was introduced into the single crosslinked PU network by simple immersion process. The second physical crosslinking was formed by numerous hydrogen bonds between urethane groups of PU and phenol hydroxyl groups in TA, which can endow PEG–PU hydrogel with good mechanical properties, self-recovery and a self-healing capability. The research results indicated that as little as a 30 mg·mL−1 TA solution enhanced the tensile strength and fracture energy of PEG–PU hydrogel from 0.27 to 2.2 MPa, 2.0 to 9.6 KJ·m−2, respectively. Moreover, the DC PEG–PU hydrogel possessed good adhesiveness to diverse substrates because of TA abundant catechol groups. This work shows a simple and versatile method to prepare a multifunctional DC single network PEG–PU hydrogel with excellent mechanical properties, and is expected to facilitate developments in the biomedical field.

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THERMOREVERSIBLE CROSS-LINKING MALEIC ANHYDRIDE GRAFTED CHLOROBUTYL RUBBER WITH HYDROGEN BONDS (COMBINED WITH IONIC INTERACTIONS)

Rubber Chemistry and Technology ◽

10.5254/rct.14.86976 ◽

2014 ◽

Vol 87 (3) ◽

pp. 459-470 ◽

Cited By ~ 3

Author(s):

Lin Li ◽

Jin Kuk Kim

Keyword(s):

Hydrogen Bonds ◽

Maleic Anhydride ◽

Ionic Interactions ◽

Cross Linking ◽

External Energy ◽

Scanning Calorimetry ◽

Ionic Bonds ◽

Cross Links ◽

Ionic Hydrogen Bonds ◽

Chlorobutyl Rubber

ABSTRACT Thermoreversible cross-linking polymers are designed based on reversible cross-linking bonds. These bonds are able to reversibly dissociate and associate upon the input of external energy, such as heat or light. Reprocessibility is possible for this kind of material. The objective was to thermoreversibly cross-link maleic anhydride grafted chlorobutyl rubber (MAH-g-CIIR) via a reaction with octadecylamine, with an excess to obtain amide-salts, which form both hydrogen bonds and ionic interactions. X-ray diffraction experiments showed the presence of microphase-separated aggregates that acted as physical cross-links for both the MAH-g-CIIR precursor and amide-salts. The tensile properties were improved by converting MAH-g-CIIR to amide-salts, because of the combination of hydrogen bonding and ionic interactions. The cross-linked materials could be repeatedly compression molded at 155 °C into homogeneous films. The differential scanning calorimetry curves and Fourier transform infrared spectra indicate that hydrogen bonds are of a thermoreversible nature, but the recovery of ionic bonds is impossible. After treatment with heating-cooling for up to three cycles, the tensile strength of the thermoreversible cross-linking CIIR was greatly reduced. The gradual reduction in the effectiveness of the ionic-hydrogen bonds is the major contribution to the reprocessibility of these materials.

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