Polymer Brushes\nSynthesized by the “Grafting-through”\nApproach: Characterization and Scaling Analysis

In this study, a combined morphological and scaling analysis\nof\nbrushes synthesized by the “grafting-through” method\nwas performed, and the possibility of regulation of the thickness\nwas revealed on an example of polyacrylamide brushes. The chemical\ncomposition of the surface in the proposed three-step approach was\nanalyzed by photoelectron and infrared spectroscopy. It was shown\nthat the thickness of the dried brush can be tuned in a controlled\nmanner by varying the polymerization temperature. The scaling dependence\nof the thickness of the dried brushes <i>d</i> on the length\nof the polymer <i>d</i> ∼ <i>L</i><sup><i>v</i></sup> was obtained by comparing reflectometry\nand dynamic light scattering data. The value of the exponent <i>v</i> = 0.82 corresponds to a rather high grafting density,\nexceeding the density of mushroom-like (ν ∼ 1/3) brushes\nand approaching the value for stretched polymer brushes (ν ∼\n1). A 10-fold increase in the polymer molecular weight leads to a\nslight decrease in grafting density by a factor of 2, which suggests\nthat the “grafting-through” approach allows obtaining\nbrushes with a high grafting density independently of attached polymer\nchain length. Herein, the possibility of attachment of uniform polymer\nbrush on large substrates with this approach was demonstrated, which\nmeans the scalability of the “grafting-through” technique.\nThe considered approach opens up a simple way for surface modification\nwith polymer nanolayers of controlled thickness.