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Full-Text Articles in Engineering
A Ph-Sensitive, Strong Double-Network Hydrogel: Poly(Ethylene Glycol) Methyl Ether Methacrylates-Poly(Acrylic Acid), Joselito Razal, G Wallace, Geoffrey Spinks, Philip Whitten, Sina Naficy
A Ph-Sensitive, Strong Double-Network Hydrogel: Poly(Ethylene Glycol) Methyl Ether Methacrylates-Poly(Acrylic Acid), Joselito Razal, G Wallace, Geoffrey Spinks, Philip Whitten, Sina Naficy
Sina Naficy
We here describe new double network (DN) hydrogels with excellent mechanical strength and high sensitivity to pH changes. The first polymer network has a bottle brush structure and is formed from oligo-monomers of poly(ethylene glycol) methyl ether methacrylate (PEGMA). Poly(acrylic acid) (PAA) is used as the second network. This double network features strong intermolecular interactions between the neutral poly(ethylene glycol) (PEG) side chains of PPEGMA and the non-ionized carboxylic acid groups of the PAA second network. When immersed in solutions with a pH below ∼4 the DN hydrogels have a low swelling ratio and are opaque as a result of …
Modulated Release Of Dexamethasone From Chitosan-Carbon Nanotube Films, Sina Naficy, Joselito Razal, Geoffrey Spinks, Gordon Wallace
Modulated Release Of Dexamethasone From Chitosan-Carbon Nanotube Films, Sina Naficy, Joselito Razal, Geoffrey Spinks, Gordon Wallace
Sina Naficy
Modulated release of dexamethasone (DEX) by electrical stimulation was investigated using chitosan (CHIT) and single walled carbon nanotubes (SWNT) host carrier films. Drug-loaded CHIT/SWNT composite films were solution-cast on carbon paper substrates. Unstimulated and stimulated release of DEX in phosphate buffer saline (PBS) solution at pH 7.4 was measured by UV–visible spectroscopy. For experiments involving electrical stimulation, the effects of voltage amplitude, electrode polarity, and SWNT content were investigated. Accelerated and complete DEX release was observed upon potentiostatic application of a negative potential (−0.8 V vs. Ag/AgCl) to the composite film, which was attributed to the electrostatic repulsions of SWNTs …
Progress Toward Robust Polymer Hydrogels, Sina Naficy, Hugh Brown, Joselito Razal, Geoffrey Spinks, Philip Whitten
Progress Toward Robust Polymer Hydrogels, Sina Naficy, Hugh Brown, Joselito Razal, Geoffrey Spinks, Philip Whitten
Sina Naficy
In this review we highlight new developments in tough hydrogel materials in terms of their enhanced mechanical performance and their corresponding toughening mechanisms. These mechanically robust hydrogels have been developed over the past 10 years with many now showing mechanical properties comparable with those of natural tissues. By first reviewing the brittleness of conventional synthetic hydrogels, we introduce each new class of tough hydrogel: homogeneous gels, slip-link gels, double-network gels, nanocomposite gels and gels formed using poly-functional crosslinkers. In each case we provide a description of the fracture process that may be occurring. With the exception of double network gels …
A Ph-Sensitive, Strong Double-Network Hydrogel: Poly(Ethylene Glycol) Methyl Ether Methacrylates-Poly(Acrylic Acid), Joselito Razal, G Wallace, Geoffrey Spinks, Philip Whitten, Sina Naficy
A Ph-Sensitive, Strong Double-Network Hydrogel: Poly(Ethylene Glycol) Methyl Ether Methacrylates-Poly(Acrylic Acid), Joselito Razal, G Wallace, Geoffrey Spinks, Philip Whitten, Sina Naficy
Sina Naficy
We here describe new double network (DN) hydrogels with excellent mechanical strength and high sensitivity to pH changes. The first polymer network has a bottle brush structure and is formed from oligo-monomers of poly(ethylene glycol) methyl ether methacrylate (PEGMA). Poly(acrylic acid) (PAA) is used as the second network. This double network features strong intermolecular interactions between the neutral poly(ethylene glycol) (PEG) side chains of PPEGMA and the non-ionized carboxylic acid groups of the PAA second network. When immersed in solutions with a pH below ∼4 the DN hydrogels have a low swelling ratio and are opaque as a result of …
Progress Toward Robust Polymer Hydrogels, Sina Naficy, Hugh Brown, Joselito Razal, Geoffrey Spinks, Philip Whitten
Progress Toward Robust Polymer Hydrogels, Sina Naficy, Hugh Brown, Joselito Razal, Geoffrey Spinks, Philip Whitten
Sina Naficy
In this review we highlight new developments in tough hydrogel materials in terms of their enhanced mechanical performance and their corresponding toughening mechanisms. These mechanically robust hydrogels have been developed over the past 10 years with many now showing mechanical properties comparable with those of natural tissues. By first reviewing the brittleness of conventional synthetic hydrogels, we introduce each new class of tough hydrogel: homogeneous gels, slip-link gels, double-network gels, nanocomposite gels and gels formed using poly-functional crosslinkers. In each case we provide a description of the fracture process that may be occurring. With the exception of double network gels …