Film Growth and Surface Roughness With Effective Fluctuating Covalent Bonds In Evaporating Aqueous Solution of Reactive Hydrophobic and Polar Groups: A Computer Simulation Model
Physics and Astronomy
A computer simulation model is proposed to study film growth and surface roughness in aqueous (A) solution of hydrophobic (H) and hydrophilic (P) groups on a simple three dimensional lattice of size L-x x L-y x L-z with an adsorbing Substrate. Each group is represented by a particle with appropriate characteristics occupying a unit cube (i.e., eight sites). The Metropolis algorithm is used to move each particle stochastically. The aqueous Constituents are allowed to evaporate while the concentration of H and P is constant. Reactions proceed from the substrate and bonded particles can hop within a fluctuating bond length. The film thickness (h) and its interface width (W) are examined for hardcore and interacting particles for a range of temperature (T). Simulation data show a rapid increase in h and W followed by its non-monotonic growth and decay before reaching steady-state and near equilibrium (h(s), W-s) in asymptotic time step limit. The growth can be described by power laws, e.g., h alpha t(gamma). W alpha t(beta) with a typical value of gamma approximate to 2, beta approximate to 1 in initial time regime followed by gamma approximate to 1.5, beta approximate to 0.8 at T = 0.5. For hardcore system, the equilibrium film thickness (h(s)) and surface roughness (w(s)) seem to scale linearly with the temperature, i.e., h(s) = 6.206 + 0.302T, W-s = 1255 + 0.425T at low T and h(s) = 6.54 + 0.198T, W-s = 1.808 + 0.202T at higher T. For interacting functional groups in contrast, the long time (unsaturated) film thickness and surface roughness, h(s) and W-s decay rapidly followed by a slow increase on raising the temperature.
Macromolecular Theory and SImulations
Bateman, S. P.,
Pandey, R. B.
(2006). Film Growth and Surface Roughness With Effective Fluctuating Covalent Bonds In Evaporating Aqueous Solution of Reactive Hydrophobic and Polar Groups: A Computer Simulation Model. Macromolecular Theory and SImulations, 15(3), 263-271.
Available at: http://aquila.usm.edu/fac_pubs/2387