Controlled RAFT Polymerization and Zinc Binding Performance of Catechol-Inspired Homopolymers

Incorporation of catechols into polymers has long been of interest due to their ability to chelate heavy metals and their use in the design of adhesives, metal–polymer nanocomposites, antifouling coatings, and so on. This paper reports, for the first time, the reversible addition–fragmentation chain transfer (RAFT) polymerization of a protected catechol-inspired monomer, 3,4-dimethoxystyrene (DMS), using commercially available trithiocarbonate, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT), as a chain transfer agent. Our identified RAFT system produces well-defined polymers across a range of molecular weights (5–50 kg/mol) with low molar mass dispersities (<i><i><i>Đ</i></i></i>, <i>M</i>_w/<i>M</i>_n < 1.3). Subsequent facile demethylation of poly­(3,4-dimethoxystyrene) (PDMS) yields poly­(3,4-dihydroxystyrene) (PDHS), a catechol-bearing polymer, in quantitative yields. Semiquantitative zinc binding capacity analysis of both polymers using SEM/EDXA has demonstrated that both PDMS and PDHS have considerable surface binding (65% and 87%, respectively), although the films deposited from PDMS are of a better quality and processability due to solubility and lower processing temperatures

The Relationship between Charge Density and Polyelectrolyte Brush Profile Using Simultaneous Neutron Reflectivity and In Situ Attenuated Total Internal Reflection FTIR

We report on a novel experimental study of a pH-responsive polyelectrolyte brush at the silicon/D₂O interface. A poly­[2-(diethylamino)­ethyl methacrylate] brush was grown on a large silicon crystal which acted as both a substrate for a neutron reflectivity solid/liquid experiment but also as an FTIR-ATR spectroscopy crystal. This arrangement has allowed for both neutron reflectivities and FTIR spectroscopic information to be measured in parallel. The chosen polybase brush shows strong IR bands which can be assigned to the N–D⁺ stretch, D₂O, and a carbonyl group. From such FTIR data, we are able to closely monitor the degree of protonation along the polymer chain as well as revealing information concerning the D₂O concentration at the interface. The neutron reflectivity data allows us to determine the physical brush profile normal to the solid/liquid interface along with the corresponding degree of hydration. This combined approach makes it possible to quantify the charge on a polymer brush alongside the morphology adopted by the polymer chains