Xiaoli Yang

A Bottom-Up Approach To Fabricate Patterned Surfaces with Asymmetrical TiO2 Microparticles Trapped in the Holes of Honeycomblike Polymer Film

Patterned bead in pore composite film with hemispherical or mushroomlike TiO(2) microparticles lying in the holes of a honeycomblike polystyrene matrix has been fabricated by a template-free bottom-up approach from a homogeneous solution of TiCl(4)/polystyrene/CHCl(3) using the breath figures method. It is a very simple way to prepare hemispherical or mushroomlike TiO(2) microparticles and to get the hexagonally nonclose-packed arrays of asymmetrical particles with or without polymer matrix, which have potential applications in photonics.

Facile preparation of hollow amino-functionalized organosilica microspheres by a template-free method

A facile method was developed to fabricate hollow amino-functionalized organosilica microspheres based on the hydrolysis and condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) in an aqueous system without an additional template and catalyst. The hollow hybrid organosilica microspheres obtained have been characterized by scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption measurements. The results of Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis displayed the composition of the synthesized hollow microspheres and the presence of amino groups on the surface. A self-templated and self-catalyzed mechanism for the formation of the hollow microspheres is proposed: the protonated APTES acts as both a catalyst for the reaction and a stabilizer for the hydrophobic precursor droplets, while the droplets themselves act as soft templates, and the consumption of the precursors leads to the formation of a hollow structure. The morphology and the size distribution of the organosilica microspheres can be controlled by tuning the composition of the precursors, and the stirring speed, as well as the reaction temperature. The large cavity with an open hole on the shell and the reactive amino groups on the surface of the hybrid organosilica microspheres promise many potential applications. Examples of employing the microspheres as adsorbents and phase change microcapsules have been presented.

Integrated poly(dimethysiloxane) with an intrinsic nonfouling property approaching "absolute" zero background in immunoassays.

The key to achieve a highly sensitive and specific protein microarray assay is to prevent nonspecific protein adsorption to an absolute zero level because any signal amplification method will simultaneously amplify signal and noise. Here, we develop a novel solid supporting material, namely, polymer coated initiator integrated poly(dimethysiloxane) (iPDMS), which was able to achieve such absolute zero (i.e., below the detection limit of instrument). The implementation of this iPDMS enables practical and high-quality multiplexed enzyme-linked immunosorbent assay (ELISA) of 11 tumor markers. This iPDMS does not need any blocking steps and only require mild washing conditions. It also uses on an average 8-fold less capture antibodies compared with the mainstream nitrocellulose (NC) film. Besides saving time and materials, iPDMS achieved a limit-of-detection (LOD) as low as 19 pg mL(-1), which is sufficiently low for most current clinical diagnostic applications. We expect to see an immediate impact of this iPDMS on the realization of the great potential of protein microarray in research and practical uses such as large scale and high-throughput screening, clinical diagnosis, inspection, and quarantine.

Robust anti-reflective silica nanocoatings: abrasion resistance enhanced via capillary condensation of APTES

This paper demonstrates a facile and effective improvement of abrasion resistance of silica nanoparticle (NP) based anti-reflective coatings via capillary condensation of 3-aminopropyl triethoxysilane (APTES). The quartz crystal microbalance (QCM) is used to test the abrasion resistance property. The versatility of this developed method is further illustrated by the successful application to the poor heat-resistant polymer substrates.

Precise preparation of highly monodisperse ZrO2@SiO2 core–shell nanoparticles with adjustable refractive indices

This paper describes a straightforward method to precisely prepare monodisperse ZrO2@SiO2 core–shell nanoparticles (CSNs) by sol–gel polymerization of TEOS in the presence of ZrO2 cores without additional capping agents. We studied the morphology and composition of CSNs by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). It has been found that the citric acid groups adsorbed onto the ZrO2 surface during the preparation of ZrO2 as well as the slow hydrolysis and condensation of TEOS in isopropanol are crucial for the selective growth of silica on the surface of ZrO2 cores. The thickness of the silica shell can be facilely controlled from about 4 to 30 nm by varying the concentration of TEOS, with the refractive indices of the prepared CSNs tuned accordingly from about 1.2 to 1.9. The coated silica shell, which can be well dispersed in solvents such as methanol and ethanol, can improve the dispersibility of pure ZrO2 nanoparticles which can only be dispersed in water. Moreover, the formation of the silica shell improved the chemical reactivity of pure ZrO2 nanoparticles. After modifying with methyltriethoxysilane (MTES), the CSNs can be well dispersed in various organic solvents, such as dimethylbenzene, chloroform and isoamyl alcohol, which may find applications in optically transparent resins with controllable refractive index or organic silicon packaging materials with high refractive index for LED and so on. Additionally, other silane coupling agents can also be applied to modify the surface chemical properties of CSNs, which may provide more potential applications.