Numerical simulation of polymerization in interdigital multilamination micromixers.

Free radical polymerization in microfluidic devices modeled with the help of numerical simulations is discussed. The simulation method used allows the simultaneous solvation of partial differential equations resulting from the hydrodynamics, thermal and mass transfer (convection, diffusion and chemical reaction). Three microfluidic devices are modeled, two interdigital multilamination micromixers respectively with a large and short focusing section, and a simple T-junction followed by a microtube reactor together considered as a bilamination micromixer with a large focusing section. The simulations show that in spite of the heat released by the polymerization reaction, the thermal transfer in such microfluidic devices is high enough to ensure isothermal conditions. Moreover, for low radial Peclet number, microfluidic devices with a large focusing section can achieve better control over the polymerization than a laboratory scale reactor as the polydispersity index obtained is very close to the theoretical limiting value. As the characteristic dimension of the microfluidic device increases, i.e. for high radial Peclet number, the reactive medium cannot be fully homogenized by the diffusion transport before leaving the system resulting in a high polydispersity index and a loss in the control of the polymerization.