Gelation speed is directly proportional to the concentration of calcium. Although the kinetics of gelation are altered by the source of calcium, the final alginate gel strength nor the resistance to calcium diffusion are altered. Calcium chloride reaches a gel strength plateau fastest ( 100 s), followed by calcium lactate ( 500 s) and calcium gluconoate ( 2000 s). Calcium chloride is the best o...

We report the dynamic light scattering study of the gelation of aqueous solutions of the biopolymer, pectin, induced by the addition of calcium chloride. The time correlation function data are analyzed under the framework of the coupling model. As the solution enters the semidilute regime where gelation sets in, the relaxation process shows a stretched exponential behavior. The stretching expon...

Excessive water production through fractures become an important problem in oil exploration of fractured reservoirs. For this purpose, polymer gels were prepared by crosslinking of aqueous solutions of polymer and crosslinker for the purpose of water management in high water cut fractured reservoirs. A copolymer of sulfonated polyacrylamide was used as polymer and chromium triacetate (Cr(OA...

Particle-tracking methods are used to study gelation in a colloidal suspension of Laponite clay particles. We track the motion of small fluorescent polystyrene spheres added to the suspension, and obtain the micron-scale viscous and elastic moduli of the material from their mean-squared displacement. The fluorescent spheres move subdiffusively due to the microstructure of the suspension, with t...

We study the formation and growth of equilibrium clusters in a suspension of weakly-charged colloidal particles and small non-adsorbing polymers. The effective potential is characterised by a short-range attraction and a long-range repulsion. The size, shape and local structure of the clusters are studied using three-dimensional particle microscopy. We observe a rapid growth in the mean cluster...

381 news & views two ferromagnetic layers. In the present case, this is the ferroelectric BaTiO 3 sandwiched between magnetic Fe and La 0.67 Sr 0.33 MnO 3 layers. Indeed, theoretical calculations 6 have predicted the possibility of significant changes in the interfacial magnetization and spin polarization in a ferromagnet in response to the ferroelectric polarization state across the interface....

Microencapsulation has become a common technique in the production of controlled release dosage forms. Many results have been reported, concerning the use of alginate beads as controlled release drug formulations. Alginate has a unique gel-forming property in the presence of multivalent cations, in an aqueous medium. Ibuprofen is an excellent analgesic and antipyretic, non-steroidal anti-inflam...

Alginate hydrogels are commonly used in biomedical applications such as scaffolds for tissue engineering, drug delivery, and as a medium for cell immobilization. Multivalent cations are often employed to create physical crosslinks between carboxyl and hydroxyl moieties on neighbouring polysaccharide chains, creating hydrogels with a range of mechanical properties. This work describes the manufa...

In order to have access to chiral gels, a series of salts derived from (1R,3S)-(+)-camphoric acid and various secondary amines were prepared based on supramolecular synthon rationale. Out of seven salts prepared, two showed moderate gelation abilities. The gels were characterized by differential scanning calorimetry, table top rheology, scanning electron microscopy, single crystal and powder X-...