In-Plane Photoalignment of Liquid Crystals by Azobenzene−Polyelectrolyte Layer-by-Layer Ultrathin Films

In-Plane Photoalignment of Liquid Crystals by Azobenzene−Polyelectrolyte Layer-by-Layer Ultrathin Film

Defect-Free Polymer Multilayers Prepared via Chemoselective Immobilization

In this paper, we investigated electrochemical properties of polymer multilayers on gold substrates using impedance spectroscopy. The multilayer was prepared by chemoselective ligation between aldehyde- and oxyamine-functionalized polymers via a layer-by-layer approach. The impedance spectra in a buffer solution in the absence of redox species revealed the formation of highly impermeable and defect-free films. The dielectric thickness of the polymer film, which is proportional to the reciprocal of capacitance, linearly increased as the number of deposition layer increased. The defect area of the polymer multilayer was obtained using the faradaic impedance with redox species. The surface coverage of eight polymer layers was determined to be 99.99%. Thus, the layer-by-layer deposition via chemoselective ligation offers a new way to prepare a highly insulating and defect-free polymer layer with finely tunable capacitance as a function of the number of deposition layers

Defect-Free Polymer Multilayers Prepared via Chemoselective Immobilization

In this paper, we investigated electrochemical properties of polymer multilayers on gold substrates using impedance spectroscopy. The multilayer was prepared by chemoselective ligation between aldehyde- and oxyamine-functionalized polymers via a layer-by-layer approach. The impedance spectra in a buffer solution in the absence of redox species revealed the formation of highly impermeable and defect-free films. The dielectric thickness of the polymer film, which is proportional to the reciprocal of capacitance, linearly increased as the number of deposition layer increased. The defect area of the polymer multilayer was obtained using the faradaic impedance with redox species. The surface coverage of eight polymer layers was determined to be 99.99%. Thus, the layer-by-layer deposition via chemoselective ligation offers a new way to prepare a highly insulating and defect-free polymer layer with finely tunable capacitance as a function of the number of deposition layers

Preparation of Aggregation Stable Gold Nanoparticles Using Star-Block Copolymers

Nanoparticles of improved stability against long-term aggregation were prepared using poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) star-block copolymer architectures. The star-block copolymers, physically resembling diblock copolymer micelles, were synthesized by anionic polymerization and coupling with ethylene glycol dimethacrylate. They contain P2VP core segments that facilitated conversion of HAuCl4 to single gold nanoparticles. The size distribution and long-term stability against aggregation of the gold nanoparticles were investigated both as solution and as films. UV−vis spectroscopy and transmission electron microscope images reveal long-term stability against aggregation up to 1 month