Fuzzy ternary particle systems by surface-initiated atom transfer radical polymerization from layer-by-layer colloidal core-shell macroinitiator particles.
ABSTRACT We report the synthesis of ternary polymer particle material systems composed of (a) a spherical colloidal particle core, coated with (b) a polyelectrolyte intermediate shell, and followed by (c) a grafted polymer brush prepared by surface-initiated polymerization as the outer shell. The layer-by-layer (LbL) deposition process was utilized to create a functional intermediate shell of poly(diallyl-dimethylammonium chloride)/poly(acrylic acid) multilayers on the colloid template with the final layer containing an atom transfer radical polymerization (ATRP) macroinitiator polyelectrolyte. The intermediate core-shell architecture was analyzed with FT-IR, electrophoretic mobililty (zeta-potential) measurements, atomic force microscopy, and transmission electron microscopy (TEM) techniques. The particles were then utilized as macroinitiators for the surface-initiated ATRP grafting process for poly(methyl methacrylate) polymer brush. The polymer grafting was confirmed with thermo gravimetric analysis, FT-IR, and TEM. The polymer brush formed the outermost shell for a ternary colloidal particle system. By combining the LbL and surface-initiated ATRP methods to produce controllable multidomain core-shell architectures, interesting functional properties should be obtainable based on independent polyelectrolyte and polymer brush behavior.
Article: A Conjugated Polymer Network Approach to Anticorrosion Coatings: Poly(vinylcarbazole) Electrodeposition[show abstract] [hide abstract]
ABSTRACT: The fabrication and characterization of poly(vinylcarbazole) (PVK)-conjugated polymer network (CPN) anticorrosion coatings on flat surfaces, steel coupons or indium tin oxide (ITO) glass substrates, is reported. Electrochemical deposition methods (potentiostatic and potentiodynamic) were employed by anodic oxidation of the carbazole side units in the PVK chains, resulting in electrodeposition of a cross-linked or network macromolecular structure. This is different from traditional conjugated polymer (CP) coatings made up of mostly linear species derived from direct electropolymerization of small molecule monomers. The coating composition was characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) allowed morphological comparison between the coatings in terms of deposition technique and surface roughness. Electrochemical impedance spectroscopy (EIS) was subsequently carried out on PVK-coated steel coupons to evaluate the performance of such coatings in an accelerated corrosion environment. The deviation from the ideal (i.e., perfectly dielectric) capacitor-like behavior and Bode plot data suggested that the CPN approach of electrodeposited PVK coatings resulted in very good protection against weathering of engineering metals.09/2010;