Dynamical heterogeneities in a colloidal fluid close to gelation are studied by means of computer simulations. A clear distinction between some fast particles and the rest, slow ones, is observed yielding a picture of the gel composed of two populations with different mobilities. Analyzing the statics and dynamics of both sets of particles, it is shown that the slow particles form a network of ...

The clinical effectiveness of tissue conditioners is influenced by their gelation characteristics and viscoelastic properties after gelation. The purpose of this study was to evaluate the effect of addition of ethyl alcohol (EtOH) on these properties, and to compare the effect of EtOH with that of the powder/liquid (P/L) ratio. Three tissue conditioners were used in this study. The gelation tim...

Purpose: To develop ampicillin trihydrate-loaded chitosan nanoparticles by modified ionic gelation method and evaluate their antimicrobial activity. Methods: Ampicillin trihydrate-loaded chitosan nanoparticles were prepared by ionic gelation method with the aid of sonication. Parameters such as the zeta potential, polydispersity, particle size, entrapment efficiency and in vitro drug release of...

the present study deals with the formulation and evaluation of chitosan nanoparticles containing donepezil hydrochloride for the targeted delivery to the brain. nanoparticles were prepared by ionic gelation method using sodium tripolyphos-phate (tpp) as a cross linking agent followed by sonication. nanoparticles were obtained in the average size ranging from 116.8 to 227.5 nm. particle morpholo...

We describe a new phenomenon in models of coalescence and fragmentation, that gel-shatter cycles. These are dynamical, unforced, stochastic cycles which slow, approximately deterministic up to beyond gelation is followed by abrupt random shattering. their appearance simulations with multiplicative kernels for spontaneous fragmentation into monomers (`shattering'). The regime such occur characte...

Many small molecules can self-assemble by non-covalent interactions into fibrous networks and thereby induce gelation of organic liquids. However, no capability currently exists to predict whether a molecule in a given solvent will form a gel, a low-viscosity solution (sol), or an insoluble precipitate. Gelation has been recognized as a phenomenon that reflects a balance between solubility and ...

Colloidal suspensions that are out of thermodynamic equilibrium undergo physical aging wherein their structure evolves to lower the free energy. In aqueous suspension of Laponite, physical aging accompanies increases of elastic and viscous moduli as a function of time. In this work, we study temporal evolution of elastic and viscous moduli at different frequencies and observe that freshly prepa...

A two-site spatial coagulation model is considered. Particles of masses m and n at the same site form a new particle of mass m + n at rate mn . Independently, particles jump to the other site at a constant rate. The limit (for increasing particle numbers) of this model is expected to be non-deterministic after the gelation time, namely, one or two giant particles randomly jump between the two s...

By William A. Eaton and James Hofrichter T HE FUNDAMENTAL cause ofsickle cell disease is the decreased deformability of the sickled red cell produced by gelation of hemoglobin S. Partial inhibition of gelation should therefore reduce clinical severity, while complete inhibition should result in a “cure.” These basic ideas have stimulated an enormous effort to understand the gelation process in ...

A series of water soluble PEG based hyperbranched polymers were successfully synthesized by homopolymerization of poly(ethylene glycol) diacrylate (PEGDA) (Mn 1⁄4 575 and 700 g mol 1 respectively) via vinyl oligomer combination. The homopolymerization of diacrylate macromers underwent a slow vinyl propagation combined with a polycondensation by coupling of reactive oligomers. At a high initiato...