Biomedical subjects

RB Pandey

Publications and source records attributed to RB Pandey.

14 recordsLinked to original sources

PubMed2000

Characteristics of driven polymer surfaces: growth and roughness

Using a Monte Carlo simulation, the growth and roughness characteristics of polymer surfaces are studied in 2+1 dimensions. Kink-jump and reptation dynamics are used to move polymer chains under a driving field where they deposit onto an impenetrable attractive wall. Effects of field (E), chain length (L(c)), and the substrate size (L) on the growing surfaces are studied. In low field, the interface width (W) shows a crossover from one power-law growth in time (W approximately t(beta(1))) to another (W approximately t(beta(2))), before reaching its asymptotic value (W(s)), with beta(1)( approximately 0.5+/-0.1)<beta(2)( approximately 0.6-1.0). For short chain lengths (L(c)=4), the saturated width (W(s)) is independent of the substrate length (L), while for long chain lengths, W(s) decays with L before becoming independent at large L. W(s) depends strongly on the magnitude of the field: for short chains, W(s) approximately E-delta with delta approximately 0.4, while for long chains, it varies nonmonotonically with E.

Journal Article↗

PubMed2000

Roughening, deroughening, and nonuniversal scaling of the interface width in electrophoretic deposition of polymer chains

Growth and roughness of the interface of deposited polymer chains driven by a field onto an impenetrable adsorbing surface are studied by computer simulations in (2+1) dimensions. The evolution of the interface width W shows a crossover from short-time growth described by the exponent beta(1) to a long-time growth with exponent beta(2) (>beta(1)). The saturated width increases, i.e., the interface roughens, with the molecular weight L(c), but the roughness exponent alpha (from W(s) approximately Lalpha) becomes negative in contrast to models for particle deposition; alpha depends on the chain length-a nonuniversal scaling with the substrate length L. Roughening and deroughening occur as the field E and the temperature T compete such that W(s) approximately (A+BT)E(-1/2).

Journal Article↗

PubMed1996