We study the relation between the directed polymer and the directed percolation models, for the case of a disordered energy landscape where the energies are taken from bimodal distribution. We find that at the critical concentration of the directed percolation, the directed polymer undergoes a transition from the directed polymer universality class to the directed percolation universality class...

Zoogloea ramigera 115 synthesized large amounts of matrix polymer from fructose, galactose, glucose, lactose, mannose, soluble starch, and sucrose when these carbohydrates were used as supplements to a chemically defined medium. All of them supported polymer synthesis to the extent that cultures thickened to a gel. Concentration of carbohydrate nutrients in the range 0.5 to 2.0% was not a criti...

In this study, the response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the preparation condition of polypropylene-grafted maleic anhydride (PP-g-MA) microporous membrane by thermally-induced phase separation (TIPS) method. A mixture of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) was used as diluent. The effect of polymer composition and qu...

We present computer simulations of the phase behaviour of an ensemble of proteins interacting with a polymer, mimicking non-specific binding to a piece of bacterial DNA or eukaryotic chromatin. The proteins can simultaneously bind to the polymer in two or more places to create protein bridges. Despite the lack of any explicit interaction between the proteins or between DNA segments, our simulat...

The stability of weak polyelectrolytes end grafted to a planar surface has been studied with a molecular theory. The effective quality of the solvent is found to depend on the interplay between polymer grafting density, acid-base equilibrium, and salt concentration. Our results reveal that increasing salt concentration results in a thermodynamically more stable layer. This reverse salt effect i...

We present a systematic study of flexible cylindrical brush-shaped macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and by dynamic light scattering (DLS) in dilute and semi-dilute solution. The SLS and SANS data extrapolated to infinite dilution lead to the shape of the polymer that can be modeled in terms of a worm-like chain with a cont...

The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was reso...

The literature on self-diffusion of polymers in solution, and on tracer diffusion of probe polymers through solutions of matrix polymers, is systematically reviewed. Virtually the entirety of the published experimental data on the concentration dependence of polymer self— and probe–diffusion is represented well by the same functional form. This form is the stretched exponential exp(−αc), where ...

1. Introduction Our understanding of polymer dynamics has greatly improved due to the reptation model and the scaling ideas. [1] According to scaling and reptation theory, the diffusion coefficient in semidilute or concentrated regimes is related to the molar mass and polymer concentration by D ~ M-2 c-1.75 and D ~ M-2 c-3 for good-solvent and θ-solvent conditions, respectively. In a limited ra...

The gas assisted injection moulding (GAIM) process has benefits realised through material saving, improved product performance and lower capital cost of machinery. This important process is similar to conventional injection moulding in so far as polymer melt enters a cavity under pressure. However, before the melt completely fills the cavity, nitrogen gas is introduced into the melt at high pre...