Autonomic self-healing in covalently crosslinked hydrogels containing hydrophobic domains

Tuncaboylu, Deniz Ceylan; Arğun, Aslıhan; Algı, Melek Pamuk; Okay, Oğuz

doi:10.1016/j.polymer.2013.09.051

Cited by 82 publications

(57 citation statements)

References 38 publications

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“…[1][2][3] Chemically cross-linked hydrogels arise from covalent bond formation, while physically cross-linked hydrogels result from intermolecular interactions such as hydrogen bonds, 4,5 p-p stacking, 6 electrostatic interactions, 7,8 ionic interactions, chain entanglements, crystallization and other non-covalent interactions. 9,10 Traditional chemically cross-linked hydrogels tend to display low mechanical strength and poor toughness, due to the inhomogeneity of the chemical crosslinking network and lack of effective energy dissipation under deformation. In order to get better mechanical properties, to date, a good deal of approaches have been proposed in an effort to obtain hydrogels with favourable mechanical properties, such as semi-IPN hydrogels, 11 slide-ring hydrogels, 12 hydrophobic association hydrogels (HA gels), [13][14][15] double-network (DN) hydrogels, [16][17][18] macromolecular microsphere composite (MMC) hydrogels 19 and nanocomposite hydrogels.…”

Section: Introductionmentioning

confidence: 99%

Self-healable, tough and highly stretchable hydrophobic association/ionic dual physically cross-linked hydrogels

Zhang

Xiang

et al. 2017

RSC Adv.

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Hydrophobic association (HA) hydrogels have recently attracted much attention since they exhibit high selfhealing ability, remolding capability and shape-memory behavior simultaneously, but their low mechanical strength prevents them from use in many stress-bearing applications. In this work, we describe a novel method for the production of tough and highly stretchable hydrogels with self-healing behavior, tensile strength of 150-300 kPa and stretch at break of 2400-2800%. Dual physical cross-linking (DPHF) hydrogels were prepared via micellar copolymerization of acrylic acid (AA) and stearyl methacrylate (C18) in an aqueous ferric chloride solution with two different types of surfactant, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS). The mechanical, rheological, selfhealing and swelling properties of the DPHF hydrogels were investigated and also evaluated as a function of the type of surfactant and the content of ferric ions. The introduction of a moderate content of ferric chloride endowed the hydrogels with excellent strength and self-healing properties simultaneously. Moreover, the structure of the DPHF hydrogels was investigated by IR and SEM analysis.The results were consistent with the results of the mechanical, self-healing and swelling properties tests.

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Section: Introductionmentioning

confidence: 99%

Self-healable, tough and highly stretchable hydrophobic association/ionic dual physically cross-linked hydrogels

Zhang

Xiang

et al. 2017

RSC Adv.

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“…[41][42][43][44][45][46][47][48] However, the co-existence of the two types of cross-links may give rise to conflicting properties, and it is still a challenge to integrate multiple functionalities such as self-healing and shape memory properties with good mechanical performance into a single component material. [41][42][43][44][45][46][47][48] However, the co-existence of the two types of cross-links may give rise to conflicting properties, and it is still a challenge to integrate multiple functionalities such as self-healing and shape memory properties with good mechanical performance into a single component material.…”

Section: Introductionmentioning

confidence: 99%

Intelligent rubber with tailored properties for self-healing and shape memory

et al. 2015

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A strategy of combining covalent and non-covalent cross-links to construct multifunctional rubber materials with intelligent self-healing and shape memory ability is demonstrated. The rubbers were prepared by self-assembly of complementary polybutadiene oligomers bearing carboxylic acid and amine groups through reversible ionic hydrogen bonds via acid-base reaction, and then further covalently cross-linking by tri-functional thiol via thiol-ene reaction. The resulting polymers exhibit self-healing and shape memory functions owing to the reversible ionic hydrogen bonds. The covalent cross-linking density can be tuned to achieve tailorable mechanical and stimuli-responsive properties: a low covalent cross-linking density remains the rubber remarkable self-healing capability at ambient temperature without any external stimulus, while a high covalent cross-linking density improves the mechanical strength and induces shape memory behavior, but effective self-healing needs to be triggered at high temperature. This strategy might open a promising pathway to fabricate intelligent multifunctional polymers with versatile functions. 9 and 9.2 mol%, respectively. Fig. 2b shows the typical FTIR spectra of pristine PB, PB-NH 2 , PB-COOH, and PB-COOH/NH 2 . For PB-NH 2 and PB-COOH, the presence of absorbance at 3382 cm -1 corresponding to -NH 2 stretching vibration and 1714cm -1 corresponding to C=O stretching vibration indicates the incorporation of amine and carboxylic acid groups into the PB backbone, respectively. For the prepared supramolecular polymer PB-COOH/NH 2 , the peak at 1714 cm -1 for neutral COOH almost completely disappears, and a new peak at 1570 cm -1 emerges, which can be attributed to carboxylate anions arising from proton transfer reaction (acid-base reaction) between carboxylic acid groups on PB-COOH and amine groups on PB-NH 2 , thus confirming the formation of ionic hydrogen bonds in the supramolecular polymers. Fig. 2 (a) 1 H NMR spectra of PB, PB-NH 2 and PB-COOH in CDCl 3 , (b) FTIR spectra of PB, PB-NH 2 , PB-COOH and supramolecular polymer PB-COOH/NH 2 .11 observed with the increase of the frequency. At low frequencies, the supramolecular interactions are able to break and re-form at the time scale probed, which is longer than the lifetime of the dynamic bonds, thus leading to a viscoelastic liquid behavior. At higher frequencies, however, the experimental time is not long enough for the supramolecular interactions to dissociate, thus the polymers exhibit elastic-like behavior. Furthermore, the crossover frequency (ω cross ) between G′ and G″ (tan δ=1) shifts to lower frequencies with the increase in covalent cross-linking density for all three samples. The lifetime of the reversible supramolecular networks can be measured as the inverse of the crossover frequency (ω cross ) of G′ and G″ (τ=1/ω). 64 Thus, the supramolecular networks with higher covalent cross-linking density possess longer life time arising from the decrease of the polymer chain mobility, which is consistent with the DSC results. Fi...

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“…In a relatively short healing time, the toughness of healed samples recovered to 1.32 MJ/m 3 , which is much higher than observed for other self-healing materials. 19,22 Moreover, the best healed sample Its fracture stress and strain is respectively about 0.43 MPa and 850%, which is rather close to 0.56 MPa and 900% of the original samples. The deviation from the average value exists mainly because this material is notch sensitive and we cannot ensure that the contact of the cut specimens is perfect and small notches may nucleate the early failure.…”

Section: Resultsmentioning

confidence: 52%

The self‐healing mechanism of an industrial acrylic elastomer

Fan

Szpunar

2015

J of Applied Polymer Sci

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The self-healing materials attract a lot of attention as self-healing ability considerably improves reliability of service and extends the life time of materials. However, the present self-healing materials lack the mechanical strength and thus cannot be used in practical applications. The industrial elastomer (VHB 4910) is a strong polymer, which has been used as dielectric actuator. Surprisingly, we observed that VHB 4910 has autonomic self-healing ability. As this is an acrylic polymer, we analyzed the hydrogen bonding between carbonyl and hydroxyl groups and demonstrated that this bonding and the molecular chain entanglement contributes to its self-healing ability. The tensile test, X-ray diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the self-healing processes. This study provides an insight into the mechanism of self-healing behavior and ability of VHB 4910 to recover its strength.

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Autonomic self-healing in covalently crosslinked hydrogels containing hydrophobic domains

Cited by 82 publications

References 38 publications

Self-healable, tough and highly stretchable hydrophobic association/ionic dual physically cross-linked hydrogels

Self-healable, tough and highly stretchable hydrophobic association/ionic dual physically cross-linked hydrogels

Intelligent rubber with tailored properties for self-healing and shape memory

The self‐healing mechanism of an industrial acrylic elastomer

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