Dissolution rate theoretical approaches

The rate of chemical weathering has been evaluated using historic, mass-balance, and theoretical-empirical mineral dissolution rate approaches, often with different results. What are these approaches and why may their results differ ... 

Theoretical approaches to dissolution rates in high concentrations of surfactant... 

Reiser expanded the diffusion model for dissolution of novolac 13-24) using percolation theory (25, 2d) as a theoretical framework. Percolation theory describes the macroscopic event, the dissolution of resist into the developer, without necessarily understanding the microscopic interactions that dictate the resist behavior. Reiser views the resist as an amphiphilic material a hydrophobic solid in which is embedded a finite number of hydrophilic active sites (the phenolic hydrogens). When applied to a thin film of resist, developer diffuses into the film by moving from active site to active site. When the hydroxide ion approaches an active site, it deprotonates the phenol generating an ionic form of the polymer. In Reiser s model, the rate of dissolution of the resin. .. is predicated on the deprotonation process [and] is controlled by the diffusion of developer into the polymer matrix (27). 

Figure 31. Theoretical polarization curves, computed on the basis of kinetic formulas taken from Tables 1 and 2 describing a preferential iron dissolution and hydrogen adsorption at kink sites concomitantly with a Volmer-Tafel hydrogen evolution reaction at the planar atoms, for ratios between the electrochemical rates approaching the limiting case II at the corrosion potential. Approximate theoretical characteristics at the corrosion potential and in the linear region at moderate polarization " = (2/er/5f)to[(C,Ci 4 )/(2A )]. A /ApH = -47 mV, = -0.60, = 30 mV dec", Voh" = U bf = 5i mW dec", vi, - = 0.5,...

The theoretical treatment of the UME response for induced dissolution processes is similar to that from SECMID (Section 13.2.1), but the boundary condition on the substrate is the rate law for the dissolution process. Various rate laws and processes for SECM-induced dissolution have been presented and described in detail (see, e.g.. Refs. [49-56]). Importantly, the SECM response (e.g., during steady-state approach curve measurements) has been shown to be able to discriminate between different candidate rate laws, providing considerable mechanistic information. 

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