Jinhan Cho

We introduce a novel and versatile approach for preparing self-assembled nanoporous multilayered films with tunable optical properties. Protonated polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and anionic polystyrene-block-poly(acrylic acid) (PS-b-PAA) block copolymer micelles (BCM) were used as building blocks for the layer-by-layer assembly of BCM multilayer films. BCM film growth is governed by electrostatic and hydrogen-bonding interactions between the opposite BCMs. Both film porosity

We examine the interactions between gold nanoparticles stabilized by the 4-(dimethylamino)pyridine (DMAP−AuNP) and various polyelectrolytes (PEs), both in solution and in layer-by-layer (LbL) assembled multilayer films. UV−vis spectrophotometry studies showed that the plasmon absorption band of the DMAP−AuNP in solution red-shifts and broadens in the presence of poly(sodium 4-styrenesulfonate) (PSS), poly(allylamine hydrochloride) (PAH), or poly(ethyleneimine) (PEI). This suggests that the polya

Polyelectrolyte multilayer thin films were prepared via the alternate deposition of poly(allylamine hydrochloride) (PAH) and a blend of poly(acrylic acid) (PAA) and poly(styrenesulfonate) (PSS). When the pH of the blend solution was 3.5, the presence of PAA in this solution significantly increased the total film thickness. With only 10 wt % PAA in the blend adsorption solution, a large increase in film thickness was observed (92 nm cf. 18 nm). It was also demonstrated that the total amount of PS

Hydrogels have diverse chemical properties and can exhibit reversibly large mechanical deformations in response to external stimuli; these characteristics suggest that hydrogels are promising materials for soft robots. However, reported actuators based on hydrogels generally suffer from slow response speed and/or poor controllability due to intrinsic material limitations and electrode fabrication technologies. Here, we report a hydrogel actuator that operates at low voltages (<3 volts) with h

Deconstructible polymeric films have potential applications in the areas of drug delivery, patterning, and membrane science. Here, we report on the preparation of heterogeneous multilayer films comprising alternate stacks of hydrogen-bonded (poly(4-vinylpyridine) (P4VP) and poly(acrylic acid, sodium salt) (PAA)) and electrostatically formed (poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH)) layers via the layer-by-layer (LbL) assembly technique. We demonstrate that

Organic field-effect transistor (OFET) memory devices made using highly stable iron-storage protein nanoparticle (NP) multilayers and pentacene semiconductor materials are introduced. These transistor memory devices have nonvolatile memory properties that cause reversible shifts in the threshold voltage (Vth ) as a result of charge trapping and detrapping in the protein NP (i.e., the ferritin NP with a ferrihydrite phosphate core) gate dielectric layers rather than the metallic NP layers employe

This review provides a comprehensive overview of the electronic effects of nano-confinement (from 1D to 3D geometries) on optoelectronic materials and their applications.

Development of soft actuators with higher performance and more versatile controllability has been strongly required for further innovative advancement of various soft applications. Among various soft actuators, electrochemical actuators have attracted much attention due to their lightweight, simple device configuration, and facile low-voltage control. However, the reported performances have not been satisfactory because their working mechanism depends on the limited electrode expansion by conven

We introduce silk textile-based water-splitting electrodes that can significantly increase the electrocatalytic performance for both HER and OER by a carbonization/interfacial assembly-driven electroplating approach.

We investigated the correlation between surface wettability and internal structure of polyelectrolyte (PE)/PE and PE/inorganic multilayer films prepared by the spin self-assembly (SA) method. Spin self-assembled poly(allylamine hydrochloride) (PAH)/poly(sodium 4-styrenesulfonate) (PSS) multilayer films deposited from PE solutions of 10 mM show the distinct oscillation in contact angles with variation of the outermost PE layer, representing the saturated values in contact angles of individual PAH

Au nanoparticle-coated highly conductive carbon fiber electrodes for high-power glucose-biofuel cells were developed based on a layer-by-layer assembling method.

Magnetic nanocomposite multilayers including magnetic nanoparticles are prepared using a nucleophilic substitution reaction between 2-bromo-2-methylpropionic acid (-BMPA) and amino (-NH2) groups. The assembly of magnetic nanoparticles in a nonpolar solvent induces densely packed adsorption, which significantly enhances the magnetic and nonvolatile memory properties of nanocomposite films. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents