High-throughput statistical characterization of poly(ethylene-co-vinyltriethoxysilane) grafting to model 2D silica surfaces via atomic force microscopy

Polymer-grafted nanomaterials have great potential in applications ranging from drug delivery to polymer nanocomposites fillers, but they are currently developed with limited access to morphological information due to their size and shape. To address this issue, we apply a high-throughput strategy using atomic force microscopy (AFM) for the study of two-dimensional substrates which act as models for their three-dimensional nanoparticle counterparts. Specifically, the oxide surfaces of silicon wafers are used as models for silica nanoparticles. Grafting is conducted by the simultaneous immersion of these silicon coupons in solutions of poly(ethylene-co-vinyltriethoxysilane). A single batch coupon reaction can contain coupons with different pretreatments or of different material compositions, or identical coupons can be subjected to the reaction for different amounts of time. Resultant grafted wafers are then assembled into grids on library slides for automated AFM image collection. Statistical analysis of the images is then used to quantitatively compare morphologies arising from different conditions. Excluded volume effects appear to influence grafting density in the resultant composites.