The molecular dynamics of poly(2-vinyl-pyridine) (P2VP) brushes is measured by Broadband Dielectric Spectroscopy (BDS) in a wide temperature (250 K to 440 K) and broad spectral (0.1 Hz to 1 MHz) range. This is realized using nanostructured, highly conductive silicon electrodes being separated by silica spacers as small as 35 nm. A "grafting-to"-method is applied to prepare the P2VP-brushes with five different grafting densities (0.030 nm(-2) to 0.117 nm(-2)), covering the "true-brush" regime with highly stretched coils and the "mushroom-to-brush" transition regime. The film thickness ranges between 1.8 to 7.1 (±0.2) nm. Two relaxations are observed, an Arrhenius-like process being attributed to fluctuations in the poly(glycidyl-methacrylate) (PGMA) linker used for the grafting reaction and the segmental dynamics (dynamic glass transition) of the P2VP brushes. The latter is characterized by a Vogel-Fulcher-Tammann dependence similar to bulk P2VP. The results can be comprehended considering the length scale on which the dynamic glass transition (≤1 nm) takes place.

The influence of swelling on the molecular dynamics of poly­(2-vinylpyridine) (P2VP) brushes is measured by broadband dielectric spectroscopy (BDS) in a broad temperature (350–420 K) and spectral (0.1 Hz–1 MHz) range with nanostructured, highly conductive silicon electrodes, separated by 35 nm high insulating silica spacers. A “grafting-to” method is applied to prepare P2VP brushes with a grafting density σ = 0.12 nm–2 and a film thickness d = 7.3 nm as measured by ellipsometry. Swelling of the P2VP brushes is realized with tetrahydrofuran (THF) vapor using a flow cell. In the dry state, the segmental dynamics of the P2VP brushes coincides with the dynamic glass transition of the bulk system while in the swollen state it becomes faster by up to 1–2 decades due to the plasticizing effect of THF.