Computer simulations of grafting

Turgman-Cohen, S. and J. Genzer, Computer simulation of controlled radical polymerization Effect of chain confinement due to initiator grafting density and solvent quality in "grafting from Method. Macromolecules, 2010. 43(22) p. 9567-9577. 

This suggests that these structures, which are the reason for the clear separation of the time scales of the local chain motion and the isotropization in PEMA, are significantly affected by the presence of the nanoparticle. One can compare this effect with the significant reduction in the chain reptation in star polymers, where the star point does not move and chain motion can only occur via arm-retraction [45]. In fact, from NMR on selectively deuterated four-arm star poly(butadiene), Brereton el al. [46] found a similar behavior, namely almost uniform dynamics for the middle part of the arm, yet significantly shorter correlation times for the chain ends. Our work also motivated computer simulation of chain dynamics of grafted chains. It was found that the repeat units at the end relax faster than units further inside along the chain, as previously observed for planar brushes but at variance with theoretical expectations [47]. 

Numerous experimental studies and computer simulations have been carried out during the last several years to check the results of these two theoretical approaches (for a recent review see [28]). The brush height can be obtained from force measurements between two brushes, since the brushes first interact when the distance between their respective grafting surfaces is 2h [18,37]. The inner structure of the brushes has been probed by small angle neutron scattering [13,14,38,39] and neutron reflectivity [21,23,24,40,41]. All these studies, as well as a number of simulations [28], give results that are consistent with the analytical SCF predictions. 

Marla, K. T. and Meredith, J. C. 2006. Simulation of interaction forces between nanoparticles End-grafted polymer modifiers. Journal of Chemical Theory and Computation 2 1624 1631. 

Fig. 6 Computer simulation and flow visualization of a dialysis needle with and without an SMP adapter. Wall shear stresses are computed along the bottom of the arteriovenous graft (a). The dialysis needle (b) is shown to produce jet impingent of flow (c), however, with the SMP adapter (d) the turbulence of the flow is decreased (e). (Reprinted with permission from [61] 2007, IEEE)...

Dong J, Li J, Zhou J Interfacial and phase transfer behaviors of polymer bmsh grafted amphiphihc nanoparticles a computer simulation study, Langmuir 30 5599-5608, 2014. 

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