Hydrophobically associated hydrogels based on acrylamide and anionic surface active monomer with high mechanical strength

Li, Wenbo; An, Hailong; Tan, Ying; Lu, Can‐Zhong; Liu, Chang; Li, Pengchong; Xu, Kun; Wang, Pixin

doi:10.1039/c2sm07200a

“…The abundant functional groups on GO nanosheets and gelatin chains induce multiple crosslinking sites on each GO nanosheet and gelatin chain, which account for the high mechanical performance of the GO-gelatin hydrogel. As expected for most physical hydrogels, 63,64 these GO-gelatin hydrogels also exhibit self-healing ability. The freshly cut pieces of hydrogel can self-heal into a whole block after they are gently pressed together (pictures not shown).…”

mentioning

confidence: 86%

Self‐assembled graphene oxide–gelatin nanocomposite hydrogels: Characterization, formation mechanisms, and pH‐sensitive drug release behavior

Piao

¹

,

Chen

²

2014

J Polym Sci B Polym Phys

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Novel physically crosslinked graphene oxide (GO)-gelatin nanocomposite hydrogels were obtained by selfassembly. The hydrogels with various ratios of GO to gelatin were prepared, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy. The static and dynamic rheological properties of the hydrogels were investigated, along with the underlying hydrogel formation mechanisms. The storage modulus of the hydrogels (containing 98-98.5 wt % water) reached 114.5 kPa, owing to the relatively strong physical bonding (i.e., hydrogen bonding and electrostatic forces) between GO and gelatin. Drug release tests showed that the drug release from the hydrogel was pH-dependent, with 96% of the model drug released in a neutral environment, compared to 28% released in an acidic medium. These hydrogels could have potential in pH-sensitive drug delivery. V C 2014

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“…However, for most tough and recoverable hydrogels based on hydrophobic associations or hydrogen bonds, the tensile fracture stresses can barely exceed ≈MPa. [14][15][16][17][18] In this work, we designed a novel physical, DN hydrogel that is tough, stiff, and recoverable. As the fi rst network, an amphiphilic triblock copolymer was employed to form a physical hydrogel (B gel) which is cross-linked by strong hydrophobic association.…”

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confidence: 99%

Tough Physical Double‐Network Hydrogels Based on Amphiphilic Triblock Copolymers

Zhang

¹

,

Sun

²

,

Zhang

³

et al. 2016

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“…

1 wileyonlinelibrary.com recoverability and self-healing property, due to their intrinsic structural heterogeneity and/or lack of effi cient energydissipation mechanisms, [ 13 ] which greatly limit their uses for other applications requiring highly mechanical properties such as cartilage, tendon, muscle, and blood vessel.Many efforts have been made to develop tough hydrogels with new microstructures and toughening mechanisms, such as double network hydrogels, [ 14 ] nanocomposite hydrogels, [ 15 ] sliding-ring hydrogels, [ 16 ] macromolecular microsphere composite hydrogels, [ 17 ] tetrapolyethylene glycol hydrogels, [ 18 ] hydrophobically associated hydrogels, [ 19,20 ] and dipole-dipole or hydrogen bonding enhanced hydrogels. [ 21,22 ] Among them, double network (DN) hydrogels have demonstrated their excellent mechanical properties.

…”

mentioning

confidence: 99%

A Novel Design Strategy for Fully Physically Linked Double Network Hydrogels with Tough, Fatigue Resistant, and Self‐Healing Properties

Chen

¹

,

Zhu

²

,

Chen

³

et al. 2015

Adv Funct Materials

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1 wileyonlinelibrary.com recoverability and self-healing property, due to their intrinsic structural heterogeneity and/or lack of effi cient energydissipation mechanisms, [ 13 ] which greatly limit their uses for other applications requiring highly mechanical properties such as cartilage, tendon, muscle, and blood vessel.Many efforts have been made to develop tough hydrogels with new microstructures and toughening mechanisms, such as double network hydrogels, [ 14 ] nanocomposite hydrogels, [ 15 ] sliding-ring hydrogels, [ 16 ] macromolecular microsphere composite hydrogels, [ 17 ] tetrapolyethylene glycol hydrogels, [ 18 ] hydrophobically associated hydrogels, [ 19,20 ] and dipole-dipole or hydrogen bonding enhanced hydrogels. [ 21,22 ] Among them, double network (DN) hydrogels have demonstrated their excellent mechanical properties. The existing knowledge of DN gels from synthesis methods, network structures, to toughening mechanisms mainly comes from chemically cross-linked DN gels. [ 23 ] Both networks with contrasting structures in DN gels are separately crosslinked by covalent bonds, [ 24 ] and the interpenetration of two contrasting networks makes the chemically linked DN gels both tough and soft, as evidenced by stiffness (elastic modulus of 0.1-1.0 MPa), strength (failure tensile stress of 1-10 MPa, strain 1000%-2000%, failure compressive stress 20-60 MPa, strain 90%-95%), and toughness (tearing fracture energy of 10 2 -10 3 J m −2 ). [ 23 ] Chemically linked DN gels have comparable toughness to cartilage and rubber. The toughening mechanisms are largely based on "sacrifi cial bonds" that break from the fi rst network to effectively dissipate energy, protect the second network, sustain stress, and store elastic energy, thus to reinforce the gels. However, the fracture of the fi rst network also causes irreversible and permanent bond breaks, making the gels very diffi cult to be repaired and recovered from damages and fatigues. [ 25 ] Thus, the internal fracture process of the fi rst network is considered to be critical for toughness enhancement, because relatively large damage zones formed in the fi rst network allow for more accumulated damage before macroscopic crack propagation occurs throughout whole networks. [ 26,27 ] Double network (DN) hydrogels with two strong asymmetric networks being chemically linked have demonstrated their excellent mechanical properties as the toughest hydrogels, but chemically linked DN gels often exhibit negligible fatigue resistance and poor self-healing property due to the irreversible chain breaks in covalent-linked networks. Here, a new design strategy is proposed and demonstrated to improve both fatigue resistance and self-healing property of DN gels by introducing a ductile, nonsoft gel with strong hydrophobic interactions as the second network. Based on this design strategy, a new type of fully physically cross-linked Agar/hydrophobically associated polyacrylamide (HPAAm) DN gels are synthesized by a simple one-pot method. Agar/ HPAAm DN gels exhibit excellent mech...

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Hydrophobically associated hydrogels based on acrylamide and anionic surface active monomer with high mechanical strength

Cited by 105 publications

References 41 publications

Self‐assembled graphene oxide–gelatin nanocomposite hydrogels: Characterization, formation mechanisms, and pH‐sensitive drug release behavior

Self‐assembled graphene oxide–gelatin nanocomposite hydrogels: Characterization, formation mechanisms, and pH‐sensitive drug release behavior

Tough Physical Double‐Network Hydrogels Based on Amphiphilic Triblock Copolymers

A Novel Design Strategy for Fully Physically Linked Double Network Hydrogels with Tough, Fatigue Resistant, and Self‐Healing Properties

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