Polymerization of Styrene with Peroxide Initiator Ionically Bound to High Surface Area Mica

Abstract

Mica powders with ultrahigh specific surface areas (ca. 100 m2/g) were treated with aqueous solutions of peroxide radical initiators bearing a single cationic group to exchange the mica surface ions with initiator cations. The stability of the initiators, the adsorption isotherms on the mica, and the adsorption equilibrium constants were measured. The resulting materials initiate the polymerization of styrene at various conditions, forming bound polymer chains in amounts up to ca. 30 wt % polymer (ca. 55 vol %) with respect to the mica. The bound chains could be removed from the surface by extraction with good solvents for poly(styrene) only when the solvent contained ions for ion exchange. On the basis of kinetic evidence, the mechanism of grafting appears to be propagation of free radicals from the surface into the monomer solution, i.e., “growth from the surface”. The results differ strongly from those previously obtained with a dicationic surface-bound azo initiator, where grafting was shown to occur by “growth to the surface”.

In Pursuit of Zero: Polymer Brushes that Resist the Adsorption of Proteins

“…[32,33] We hypothesized that coatings of this nature would be a prerequisite for protein resistance, based on the findings of Whitesides, Grunze, and others. [6,16,34] Many polymerization mechanisms have been realized in a SIP format, including living cationic and anionic polymerization, [35,36] ring-opening metathesis polymerization, [37,38] condensation polymerization, [39,40] free-radical polymerization, [32,[41][42][43] and atom-transfer radical polymerization (ATRP). [44][45][46][47] We chose ATRP largely because it is simple to perform, affords good control of polymerization kinetics, and is compatible with a range of solvents.…”

Nanocomposites from Layered Silicates: Graft Polymerization with Intercalated Ammonium Peroxides

“…[11] With I intercalated into Na þ -montmorillonite as initiator, indeed, we observed butyl acrylate polymerization with high conversion (> 60%). However, virtually no polymers were grafted on the layered silicate.…”

“…[11] Due to the temperature sensitivity of the peroxides, solvent evaporation and product drying was performed at 50 mbar/30 8C, unless stated otherwise. NMR spectra were measured on a Bruker Avance 300 NMR spectrometer at 300 MHz ( 1 H) and 75 MHz ( 13 C), respectively, and referenced to SiMe 4 (d in ppm, J in Hz).…”

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

“…After a treatment with 3-glycidoxypropyltrimethoxysilane on silanol, a chemical reaction was performed between acid group of 4,4'azobis(4-cyanovaleric acid) and epoxy group linked on the silicon wafer. Using the same strategy, Velten et al [188] attached peroxide initiators with cationic group to mica surface via ionic exchange.…”