Macromolecules, Vol.49, No.23, 9272-9282, 2016
Photocontrollable Self-Assembly of Azobenzene-Decorated Nanoparticles in Bulk: Computer Simulation Study
Decoration of nanoparticles by specific functional groups provides means of controlling their aggregation and self-assembly into ordered morphologies. We study the photocontrollable self-assembly of the azobenzene-functionalized nanopartides using coarse-grained molecular dynamics simulations. With no illumination applied, a monodomain smectic morphology is formed only via cooling the isotropic system at a sufficiently slow rate. Quenching the system below the smectic isotropic transition results in formation of a polydomain glass-like state with restricted dynamics of nanopartides. Upon irradiation with appropriate wavelength and intensity, the azobenzenes undergo trans-cis-trans photoisomerization cycles which unlock the interdomain links and induce uniaxial orientation of domains with their local director perpendicular to the polarization axis of irradiation. As demonstrated by the simulations, this transition can speed up essentially the self-assembly of decorated nanopartides from the isotropic to the monodomain smectic phase, both via gradual cooling down and via quenching in a broad temperature interval below the smectic isotropic transition.