New Colloidal Lithographic Nanopatterns Fabricated by Combining Pre-Heating and Reactive Ion Etching

We report a low-cost and simple method for fabrication of nonspherical colloidal lithographic nanopatterns with a long-range order by preheating and oxygen reactive ion etching of monolayer and double-layer polystyrene spheres. This strategy allows excellent control of size and morphology of the colloidal particles and expands the applications of the colloidal patterns as templates for preparing ordered functional nanostructure arrays. For the first time, various unique nanostructures with long-range order, including network structures with tunable neck length and width, hexagonal-shaped, and rectangular-shaped arrays as well as size tunable nanohole arrays, were fabricated by this route. Promising potentials of such unique periodic nanostructures in various fields, such as photonic crystals, catalysts, templates for deposition, and masks for etching, are naturally expected

"Nanohybrids" based on pH-responsive hydrogels and inorganic nanoparticles for drug delivery and sensor applications.

Allyl-PEG capped inorganic NPs, including magnetic iron oxide (IONPs), fluorescent CdSe/ZnS quantum dots (QDs), and metallic gold (AuNPs of 5 and 10 nm) both individually and in combination, were covalently attached to pH-responsive poly(2-vinylpyridine-co-divinylbenzene) nanogels via a facile and robust one-step surfactant-free emulsion polymerization procedure. Control of the NPs associated to the nanogels was achieved by the late injection of the NPs to the polymerization solution at a stage when just polymeric radicals were present. Remarkably, by varying the total amount of NPs injected, the swelling behavior could be affected. Furthermore, the magnetic response as well as the optical features of the nanogels containing either IONPs or QDs could be modified. In addition, a radical quenching in case of gold nanoparticles was observed, thus affecting the final nanogel geometry

Elaboration of photonic crystal heterostructures by the Langmuir–Blodgett method

This paper describes the elaboration of photonic crystal heterostructures with a perfectly defined architecture. The transfer of a Langmuir film of functionalized silica particles onto a solid substrate gave us the ability to build three-dimensional (3D) colloidal crystals. The influence of the withdrawing speed of the substrate on the crystalline quality of the 3D photonic materials has been studied. Photonic crystal heterostructures have been fabricated by the successive depositions of layers of silica spheres with different diameters. The composite materials have been characterized by scanning electron microscopy (SEM) and near infrared (NIR) spectroscopy. Our results establish that the optical properties of these multilayer systems can be tailored by adjusting either the thickness or the stacking order of each component crysta

Colloidal Crystals as Templates for Macroporous Carbon Electrodes of Controlled Thickness

Macroporous carbon films were synthesized using colloidal crystals as a template and were characterized using scanning electron microscopy (SEM) and Raman spectroscopy. The colloidal crystals were elaborated by the Langmuir-Blodgett technique and were infiltrated with carbon by a controlled chemical vapor infiltration (CVI) process. After removal of the template, thin free-standing carbon membranes whose thicknesses match perfectly those of the templates were obtained. Their ability to act as electrodes was checked by carrying out cyclic-voltammetry experiments

Rational Design of Enzyme-Modified Electrodes for Optimized Bioelectrocatalytic Activity

The immobilization of bilirubin oxidase (BOD) on macroporous gold electrodes for the optimization of bioelectrocatalytic activity is described. A bilirubin oxidase mutant S362C (cys-BOD) engineered with a cysteine residue located on purpose at the enzyme surface close to the T1 active center was used. It allows the attachment in one-step of a self-assembled monolayer of the enzyme to gold through a reaction between the thiol group of the cysteine residue and the metal surface. BOD immobilization of wild type and S362C mutant in macroporous gold electrodes allowed high retention of activity and perfect control of the overall BOD loading due to the fine-tuning of the macroporous structure. The macroporous arrangement together with the use of cys-BOD makes these rationally designed enzyme-modified electrodes very promising candidates for high-performance bioelectrocatalytic devices with improved activity and stability

Surface assisted nucleation and growth of polymer latexes on organically-modified inorganic particles

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