Hydrogels: Methods of Preparation, Characterisation and Applications

Gulrez, Syed K. H.; Al-Assaf, Saphwan; Phillips, Glyn O.

doi:10.5772/24553

Cited by 208 publications

(164 citation statements)

References 128 publications

(132 reference statements)

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“…All polyanions used in the investigation have carboxyl groups [20,21]. e mixture of the different polyanions with the CS produced a hydrogel at a pH lower than 4, and the morphology of hydrogels is very sensitive to the preparation procedures [16,22,23].…”

Section: Resultsmentioning

confidence: 99%

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Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Henao

Delgado

Contreras

et al. 2018

International Journal of Chemical Engineering

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e preparation of gels by charge interaction methods has been extensively studied, but it is not yet clear how these methods influence gel characteristics. e objective of this work was to study differences in morphology and surface charge of hydrogels prepared by ionotropic gelation, polyelectrolyte complexation, and a combination of both methods. us, the anionic charge was provided by carboxymethylcellulose (CMC), carboxymethylated starch (CMS), and alginic acid (AA); calcium chloride (CaCl 2 ) and chitosan (CS) were used for the ionotropic gelation and polyelectrolyte complexation, respectively. ose materials are commercially available, have low toxicity, and are widely used in the area. ese compounds interact through physical crosslinks, which are affected by physical changes of the medium. Our results showed that these two methods produced changes in the morphology of the hydrogels. CMC gels exhibited larger pores in the presence of CaCl 2 . In polyelectrolyte complexation, CMS produced an increased agglomeration of particles, while the addition of CaCl 2 to AA generated dispersed particles of size in the order of millimeters. Mixing both ionotropic gelation and polyelectrolyte complexation methods yielded gels of varied charge (568 mV for CMC, 502 mV for CMS, and 1713 mV for AA). FTIR spectra of the hydrogels showed interactions between the different polymeric compounds, being the greatest changes between 1250 and 1600 cm −1 , due possibly to the replacement of Na by Ca at crosslinking points. erefore, the method of gel preparation employed had a major influence on the size and pore distribution, parameters which in turn influence encapsulation and drug delivery in these systems.

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Section: Resultsmentioning

confidence: 99%

“…In this study, differences which are related to the method used in each polymer gel were observed from SEM images. Gulrez et al [21] claim that, at acidic pHs, the mechanism promotes hydrogen bonding, which induces a decrease in the solubility in water and results in the formation of an elastic hydrogel.…”

Section: Resultsmentioning

confidence: 99%

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Henao

Delgado

Contreras

et al. 2018

International Journal of Chemical Engineering

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“…Gels of this type can be obtained by dissolving Na-CMC in 0.1 M of HCl (Gulrez et al 2011) or adding poly (vinyl alcohol) to an aqueous solution of Na-CMC (Congming and Yongkang 2008). Yang and Zhu (2007) have observed that the viscosity of Na-CMC aqueous solutions rises rapidly after the addition of glycerin.…”

Section: Introductionmentioning

confidence: 99%

Effect of the degree of substitution on the rheology of sodium carboxymethylcellulose solutions in propylene glycol/water mixtures

2017

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The linear dynamic viscoelastic properties and non-linear transient rheology of sodium carboxymethylcellulose solutions (Na-CMC) in propylene glycol/water mixtures were investigated. Measurements were carried out for the solutions of Na-CMC with three different degrees of substitution (DS), namely 0.62, 0.79, 1.04, and the similar average molecular weight (M w & 250,000 g/mol). The strong synergism between the molecules of Na-CMC with DS of 0.62 and 0.79, and propylene glycol has been observed. The occurrence of the overshoot shear stress and the low loss tangent values indicate the physical cross-linking of the polymer chains. The increase of propylene glycol concentration over 80 wt% and sodium carboxymethylcellulose (DS = 0.7) over 1.6 wt% leads to the formation of a physical cross-link network. The absence of overshoot shear stress and terminal behaviour in SAOS flow of the Na-CMC 1.04 solutions in the PG/water mixture shows that no intermolecular cross-linking of polymer chains occurred in them.

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“…The sample is a single part composed of two regions according to the materials used in the experiments. It consists of a continuous region of PDMS silicone elastomer surrounding the PA hydrogel material modeled as water given its large water content [10]. The…”

Section: Numerical Modelingmentioning

confidence: 99%

Novel method to dynamically load cells in 3D-hydrogels culture for blast injury studies

Sory

Areias

Overby

et al. 2017

AIP Conference Proceedings

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Hydrogels: Methods of Preparation, Characterisation and Applications

Cited by 208 publications

References 128 publications

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Effect of the degree of substitution on the rheology of sodium carboxymethylcellulose solutions in propylene glycol/water mixtures

Novel method to dynamically load cells in 3D-hydrogels culture for blast injury studies

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