Triblock cylinders at fluid-fluid interfaces.

We present the interactions and assembly of triblock cylinders at oil-water and air-water interfaces. ABA-type triblock cylinders with different block ratios and surface wettabilities are prepared using a micromolding method. These triblock cylinders at fluid-fluid interfaces induce complex interface deformation depending upon their relative block ratio and the surface wettability.

Effects of anionic surfactants on the water permeability of a model stratum corneum lipid membrane.

The stratum corneum (SC) is the ourtermost layer of the epidermis and has a brick-and-mortar-like structure, in which multilamellar lipid bilayers surround flattened dead cells known as corneocytes. The SC lipid membranes provide the main pathway for the transport of water and other substances through the SC. While the physicochemical properties of the SC can be affected by exogenous materials such as surfactants, little is known about how the water barrier function of the SC lipid membranes is compromised by common surfactants.

Double hydrophilic Janus cylinders at an air-water interface.

Colloidal particles spontaneously attach to the interface between two immiscible fluids to minimize the interfacial area between the two phases. The shape and wettability of particles have a strong influence on their configuration and interactions at fluid-fluid interfaces. In this study, we investigate the behavior of asymmetrically hydrophilic Janus cylinders (or double hydrophilic Janus cylinders with two different hydrophilic regions) trapped at an air-water interface.

One-step index-tunable antireflection coatings from aggregated silica nanoparticles.

We demonstrate a method for producing thickness- and refractive index-tunable antireflection coatings utilizing a one-step spin coating procedure with silica nanoparticle solutions. Aging nanoparticle solutions under controlled pH and temperature induces aggregation, allowing precise control of the porosity and refractive index of the spin-processed coating. Coating thickness measurements as a function of solution aging time and temperature allow for determination of the activation energy of the reaction-limited aggregation process.

Mechanical reinforcement of nanoparticle thin films using atomic layer deposition.

Thin films composed of nanoparticles exhibit synergistic properties, making them useful for numerous advanced applications. Nanoparticle thin films (NTFs), however, have a very low resistance to mechanical loading and abrasion, presenting a major bottleneck to their widespread use and commercialization. High-temperature sintering has been shown to improve the mechanical durability of NTFs on inorganic substrates; however, these high-temperature processes are not amenable to organic substrates.

Photocatalytic and conductive MWCNT/TiO2 nanocomposite thin films.

A conductive and photocatalytic nanocomposite thin film comprising multiwalled carbon nanotubes (MWCNTs) and TiO2 nanoparticles is fabricated based on layer-by-layer (LbL) assembly in a nonpolar solvent, toluene. An amphiphilic surfactant, aerosol OT (AOT), is used to impart opposite surface charge onto MWCNTs and TiO2 in toluene. Our fabrication technique enables the incorporation of unoxidized MWCNTs into the nanocomposite thin films, and at the same time, provides a versatile method of fabricating conformal thin films over a large area.

Layer-by-layer assembly of charged particles in nonpolar media.

Layer-by-layer (LbL) assembly of charged species such as nanoparticles and polymers has been widely used to generate functional thin films with unique wetting, optical, catalytic, and biological properties. Although LbL assembly is a versatile tool for creating functional thin films on a variety of substrates, it is generally restricted to aqueous media, in which electrolytes ionize readily due to the large dielectric constant of water. LbL assembly of non-water-soluble materials would expand the range of film properties and functionalities that are attainable.