Dong‐Pyo Kim

Abstract This study presents a method for the fabrication of solvent‐resistant poly(dimethylsiloxane) (PDMS) microfluidic devices by coating the microfluidic channel with a hybrid inorganic/organic polymer (HR4). This modification dramatically increases the resistance of PDMS microfluidic channels to various solvents, because it leads to a significant reduction in the rate of solvent absorption and consequent swelling. The compatibility of modified PDMS with a wide range of solvents is investiga

During the solution reaction of NaBH4/(NH4)2SO4 in tetraglyme to form borazine, polymeric aminoborane (NH2BH2)x has been isolated as a white powder. The powder was characterized by thermal gravimetric analysis/differential scanning calorimetry, infrared and mass spectroscopies, and powder X-ray diffraction. Solid-state 15N and 11B nuclear magnetic resonance firmly proved that the chain-like poly(aminoborane) evolved a partially condensed B3N3 ring structure by dehydrogenative condensation betwee

Putting osmium in its place: The immobilization of hazardous OsO4 on polymer nanobrushes in a microreactor is a safe, effective, and green concept. The method allows reactions to be performed in a time- and chemical-saving manner, with little environmental impact, as compared to spill-over bulk processes.

Converting solar energy to chemical energy via photocatalysis has attracted increasing interest. Simultaneously realizing efficient charge separation and fast reactant/product diffusion/transport is highly significant for improving the photocatalytic activity, which however is difficult. Herein, we reported an interfacially confined strategy by constructing interfacial pores as nanoreactors between metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) with controlled surface wet

An efficient cell transformation method is presented that utilizes droplet electroporation on a microfluidic chip. Two types of green microalgae, a wall-less mutant and a wild type of Chlamydomonas reinhardtii, are used as model cells. The PDMS-glass electroporation chip is simply composed of a flow-focusing microstructure for generating cell-encapsulating droplets and a serpentine channel for better mixing of the content in the droplet, and five pairs of parallel microelectrodes on the glass sl

The synthesis of pharmaceutical compounds via short-lived intermediates in a microreactor is attractive, because of the fast flow and high throughput. Additionally, intermediates can be utilized sequentially to efficiently build up a library in a short time. Here we present an integrated microfluidic synthesis of biologically active thioquinazolinone libraries. Generation of o-lithiophenyl isothiocyanate and subsequent reaction with aryl isocyanate is optimized by controlling the residence time

Three-dimensionally long range ordered macroporous SiC ceramics were prepared using a low molecular weight polymer precursor, polymethylsilane (PMS), by utilizing sacrificial colloidal silica crystalline arrays as templates which were subsequently etched off with HF (45%) after pyrolysis in an argon atmosphere. SEM, TEM, HRTEM and BET were used to specify the morphologies and BET surface areas of the porous materials. The pore sizes of about 84–658 nm and BET surface areas (pore volumes) of abou

Recently, metal-organic frameworks (MOFs) with multifunctional pore chemistry have been intensively investigated for positioning the desired morphology at specific locations onto substrates for manufacturing devices. Herein, we develop a micro-confined interfacial synthesis (MIS) approach for fabrication of a variety of free-standing MOF superstructures with desired shapes. This approach for engineering MOFs provides three key features: 1) in situ synthesis of various free-standing MOF superstru

Microreactors fabricated with optically transparent inorganic polymers from two types of precursors using a UV-microimprinting process demonstrated reliable solvent resistance and capability for performing three model organic synthetic reactions, which were compared with batch systems and glass based microreactors.

Three-dimensional long range ordered hollow SiC and filled SiCN sphere assemblies were prepared for the first time by embedding low molecular weight pre-ceramic polymers of polymethylsilane and polysilazane into sacrificial 3DOM carbon templates which were subsequently burned out in air after pyrolysis under a nitrogen atmosphere.

Keep on running: A microchemical system for continuous flow catalytic reactions with a magnetic catalyst is presented (see picture). It enables the automatic separation and recirculation of catalyst particles and is applicable to various catalytic reactions. Microfluidic systems have provided new concepts and challenging subjects for new chemical processes.1 The advantages offered are increased surface area to volume ratio, rapid mass- and heat-transfer, enhanced process safety, simple feasibili

In this report we have described fabrication of preceramic polymer-derived transparent, solvent-resistant, thermally stable and bio-compatible microchannels and substrates using soft-lithography methods such as micromolding in capillary (MIMIC) and micromolding. The micromolding technique was preferred in the current work to fabricate channels by thermal and photo crosslinking of a commercially available poly(vinyl silazane) (VL 20, KION Corporation, USA). Both thermal and photo cured preceramic

Boron nitride (BN) matrix composites reinforced by a number of different ceramic fibers have been prepared using a low‐viscosity, borazine oligomer which converts in very high yield to a stable BN matrix when heated to 1200°C. Fibers including Nicalon (SiC), FP (A1 2 O 3 ), Sumica and Nextel 440 (Al 2 O 3 ‐SiO 2 ) were evaluated. The Nicalon/BN and Sumica/BN composites displayed good flexural strengths of 380 and 420 MPa, respectively, and modulus values in both cases of 80 GPa. On the other han