A new approach to micropatterning is demonstrated. The approach is based on driving an electrochemical process at the solid-liquid interface through the formation of a flux of ions from a micropipet that is held in close proximity to the surface. The flux of ions is generated by the so-called potential assisted ion transfer at the interface between two immiscible electrolyte solutions (ITIES). As a model system, the local deposition of silver was examined. Specifically, a constant potential, which was applied to a micropipet filled with an aqueous solution of silver ions, caused the transfer of Ag(+) into the outer nitrobenzene (NB) solution that consisted of an electrolyte, tetrabutylammonium tetrakis[4-chlorophenyl]borate (TBATPBCl). To facilitate the transfer of silver ions a macrocyclic ligand, that is, dibenzo-24-crown-8 (DB24C8), was added to the organic phase. The Faradaic current of this micro-ITIES was used as a means of controlling the tip-surface distance in scanning electrochemical microscopy (SECM) and depositing silver microstructures on a gold substrate.[on SciFinder (R)]

A new approach to micropatterning is demonstrated. The approach is based on driving an electrochem. process at the solid-liq. interface through the formation of a flux of ions from a micropipet that is held in close proximity to the surface. The flux of ions is generated by the so-called potential assisted ion transfer at the interface between two immiscible electrolyte solns. (ITIES). As a model system, the local deposition of silver was examd. Specifically, a const. potential, which was applied to a micropipet filled with an aq. soln. of silver ions, caused the transfer of Ag+ into the outer nitrobenzene (NB) soln. that contained an electrolyte, tetrabutylammonium tetrakis[4-chlorophenyl]borate (TBATPBCl). To facilitate the transfer of silver ions a macrocyclic ligand, i.e., dibenzo-24-crown-8 (DB24C8), was added to the org. phase. The faradaic current of this micro-ITIES was used as a means of controlling the tip-surface distance in scanning electrochem. microscopy (SECM) and depositing silver microstructures on a gold substrate. [on SciFinder(R)]

The affinity of selected metal ions for palmitic (PAL) and hexadecanesulfonic acid (HDSA) monolayers self-assembled onto an octadecyl silane (ODS) monolayer covalently bound to a Ge internal reflection element has been examd. in situ in aq. electrolytes by attenuated total reflection Fourier transform IR spectroscopy. Marked changes in the bands assocd. with the sym. and asym. stretches of the carboxylate groups induced by metal-ion binding could be discerned for PAL/ODS self-assembled bilayers (SABs) in contact with Cd2+ solns. of pH = 6 even at concns. in the sub-μM range. Subsequent exposure of Cd2+/PAL/ODS SABs to solns. of pH < 4 devoid of Cd2+ led to the removal of Cd2+ from the bilayer leaving behind a better ordered structure, as judged by the shift of the C-H stretching modes toward lower wavenumbers. Spectral evidence for strong metal-terminal sulfonate group interactions was also obtained for HDSA/ODS SABs immersed in solns. contg. Cd2+, Fe3+, and Fe2+, for which the effects on the characteristic sym. and asym. modes of the terminal sulfonate moieties were found to be unique to the nature of each of the metal ions. [on SciFinder(R)]

High-quality self-assembled monolayers of long-chain alcs. were formed on H-terminated cryst. and porous Si surfaces under mild conditions in a 1-step reaction using iodoform as an in-situ iodinating agent. Besides the convenient conditions under which the procedure is carried out, it yields a high surface coverage and suppresses oxide formation. In-situ iodination is advantageous over other direct methods as it probably forms very reactive intermediate species, e.g. Si-I, that channel the reaction via a nucleophilic attack to form highly dense monolayers. [on SciFinder(R)]