Study and Application of a Linear Frequency−Thickness Relation for Surface-Initiated Atom Transfer Radical Polymerization in a Quartz Crystal Microbalance

Abstract

A linear frequency−thickness (F−T) relation was established for surface-initiated atom transfer radical polymerization (SI-ATRP) in a quartz crystal microbalance (QCM). This quantitative F−T relation is monomer dependent but independent of polymerization rate, initiator and polymer density. With this F−T relation and the online monitoring capacity, QCM was successfully applied to study the kinetics of SI-ATRP mechanisms. QCM was also demonstrated to be useful in controlling film thickness at the angstrom level, which is critical in nanofabrication.

The change in thickness of the solidified liquid layer rather than the immobilized mass determines the frequency response of a quartz crystal microbalance

“…The dry thickness of poly(OEGMA-co-HEMA) was 14.6 nm as determined by ellipsometry, which also gave a 104 Hz (overtone number n = 3) frequency decrease compared to the bare chip in air and a k 2 value (the ratio of frequency and thickness) of 7.2, which agreed well with the reported linear thickness-frequency relation [25,26]. The terminal hydroxyl groups of poly(OEGMA-co-HMEA) were then converted to carboxyl groups by reacting with succinic anhydride [27].…”

Surface Initiated Polymerizations via e-ATRP in Pure Water

“…This linearity indicate the lack of free radical formation which would show a fast polymerization in combination with a quick leveling off with respect to the mass increase and also not having the possibility of reinitiation. While similar behavior with respect to difference between initial polymerization and re-initiation as well as for the average increase in mass over time (0.54-4.32 ng·s (values given recalculated to achieve ng·s −1 ) depending on the monomer/catalyst ratio with OEGMA 475 as the monomer) was found for conventional ATRP [38], the development of mass deposition was shown to be much less controlled and displays a decreased mass accumulation over time [38,39]. It has to be noted that the mass deposition is composed of a combination of polymer with additional components such as water and other solubilized species confined in the polymer layer.…”

Comparison of two “grafting from” techniques for surface functionalization: Cathodic electrografting and surface-initiated atom transfer radical polymerization

“…Fig. 7 shows a typical frequency vs. time curve, which shape is similar to previous published studies [28]. Although we did not perform a complete kinetic study, that result confirms that the SI-ATRP process was successful in our conditions (0.20 kHz corresponds to 50 nm).…”