Andrew K Bohaty

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The interior surface of the glass nanopore electrode was modified with spiropyran moieties to impart photochemical control of molecular transport through the pore orifice (15-90 nm radius). In low ionic strength acetonitrile solutions, diffusion of a positively charged species (Fe(bpy)(3)(2+)) is electrostatically blocked with approximately 100% efficiency(More)
We prepared robust free-standing 200 microm-thick colloidal membranes (nanofrits) with a relatively large area and no mechanical defects by sintering silica colloidal films. The silica spheres used to prepare the nanofrits were 338, 300, or 251 nm in diameter, leading to 25, 22.5, and 19 nm nanopore sizes, respectively. The room-temperature diffusional flux(More)
The influence of pH and ionic strength on permselective transport in nanoporous opal films prepared from 440 nm silica spheres was investigated by cyclic voltammetry in aqueous and acetonitrile solutions. Three-layer opal films were deposited from a 1.5 wt % colloidal solution of silica spheres onto 25-microm-diameter Pt microdisk electrodes shrouded in(More)
Thin-film opals comprising three layers of 440 nm diameter SiO2 spheres were assembled on Pt electrodes and modified with amino groups on the silica surface. Diffusion of anionic, cationic, and neutral redox species through the opals was studied by cyclic voltammetry. The chemically modified opal membranes demonstrate high molecular throughput and, at low(More)
Suspended self-assembled opal membranes have been prepared from 440- or 170-nm-diameter silica spheres by evaporation of their colloidal solutions over vertically oriented 0.3-mm-thick silicon wafers containing frustum-shaped openings. Robust 0.5 x 0.5 mm(2) membranes with a thickness of ca. 300 mum have been reproducibly prepared using 170 nm silica(More)
Star polymers with poly(ethylene glycol) (PEG) arms and a degradable cationic core were synthesized by the atom transfer radical copolymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate macromonomer (PEGMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and a disulfide dimethacrylate (cross-linker, SS) via an "arm-first" approach. The star(More)
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