A facile method towards rough morphology polymer brush for increased mobility of embedded nanoparticles

•A simple method to obtain polymer brush with rough nanoscale morphology is demonstrated.•Roughness can be controlled by varying solvent qualities during the first and second round growths.•Rough nanoscale morphology resulted in better mobility of incorporated gold nanoparticles.

The control of polymer brush morphology is important in determining its performance for various applications such as for anti-fouling coatings or as a host for polymer brush-nanoparticle nanocomposites. Herein we introduce a novel method to vary the surface roughness of polymer brushes by sequential growth in different solvent qualities. Poly(oligo ethylene glycol) methacrylate (POEGMA) was first grown homogeneously using a solvent of 20% water in methanol. A second round of synthesis was then performed with varying ratio of methanol-to-water and ethanol-to-water. We found that roughness generally increased with higher water content during the second round synthesis. Finally we observed, through incorporating as-prepared gold nanoparticles into POEGMA, that nanoparticle distribution and mobility could be improved by having a rougher surface morphology. These findings could be beneficial in designing localized surface plasmon resonance (LSPR)-based solid phase sensing platforms that rely on gold nanoparticle re-organization in polymer brushes.

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