The gelation of water suspension of a synthetic clay (Laponite) has been studied by dynamic light scattering in a wide range of clay weight concentration (C(w)=0.003-0.031). At variance with previous determination, indicating a stable liquid phase for C(w)<C(*)(w) approximately 0.015-0.018, we find that gelation actually takes place in the whole examined C(w) range. We find also that C(*)(w) ma...

The present work investigated the preparation of biodegradable beads with alginate polymer by ionotropic gelation method to improve the control release properties of the antibiotic rifampicin. Ionotropic gelation method was applied to prepare beads using calcium chloride (CaCl2) as cationic component and alginate as an anionic component. In this method, adding 0.5% w/v polyvinyl alcohol (PVA) t...

We investigated the temperature-responsive gelation of collagen/genipin solutions using pepsin-solubilized collagen (PSC) and acid-solubilized collagen (ASC) as substrates. Gelation occurred in the PSC/genipin solutions at genipin concentrations 0-2 mM under moderate change in temperature from 25 to 37°C. The PSC/genipin solutions exhibited fluidity at room temperature for at least 30 min, wher...

Chemical systems that remain kinetically dormant until activated have numerous applications in materials science. Herein we present a method for the control of gelation that exploits an inbuilt switch: the increase in pH after an induction period in the urease-catalyzed hydrolysis of urea was used to trigger the base-catalyzed Michael addition of a water-soluble trithiol to a polyethylene glyco...

Polyacrylonitrile (PAN) gel was prepared by the freezing and thawing method using the solvents of N,N-dimethylacetamide (DMA) and tetramethylene sulfone(sulfolane). The gelation time after a series of freezing and thawing was examined with varying PAN concentration of DMA solution and the freezing time. Dynamic viscoelasticity was measured in the course of gelation for DMA solution to observe t...

An organogelator was produced and identified from a dynamic imine system, resolved and amplified by selective gelation. The formation of the organogel was monitored in situ by (1)H NMR, showing the existence of multiple reversible reactions operating simultaneously, and the redistribution of the involved species during gelation. The formed organogelator proved effective with a range of organic ...

We use molecular dynamics simulations to show that glass transition in a model phase separating amorphous alloy, Cu(50)Nb(50), occurs by gelation. At the glass transition, a mechanically stiff, percolating network of atoms with icosahedral local packing forms at the interfaces between compositionally enriched regions. This low-energy network halts coarsening of the phase-separated structure and...

Some systems show high miscibility in water at low temperatures while they phase separate at high temperatures. Before the macroscopic phase separation there is a strong turbidity, defined as clouding [1, 2]. At certain circumstances, namely above a critical concentration, the polymer system stays turbid with a gel-like appearance, without any macroscopic phase separation [3]. Gels defined in t...

A laser photolysis technique has been developed to assess the quantitative significance of the delay time of hemoglobin S gelation to the pathophysiology of sickle cell disease. Changes in the saturation of hemoglobin S with carbon monoxide produced by varying the intensity of a photolytic laser beam were used to simulate changes in the saturation of oxyhemoglobin S produced by variations in ox...

We fabricate thermo-responsive polymer microgels by combining microfluidic pre-gel emulsification with polymer-analogous gelation. This separates the microgel formation from the polymer synthesis; it combines highly controlled microfluidic templating with the great flexibility of preparative polymer chemistry, allowing each to be controlled independently. We produce monodisperse pre-gel droplet...