Optimising a vortex fluidic device for controlling chemical reactivity and selectivity

Facile synthesis of electrochemically active Pt nanoparticle decorated carbon nano onions

Well dispersed platinum nanoparticles (∼2 nm) on carbon nano-onions are accessible using a simple and scalable one-step batch method.

Rapid high conversion of high free fatty acid feedstock into biodiesel using continuous flow vortex fluidics

Rapid reduction of free fatty acids in biodiesel feedstock: the rapid conversion of problematic free fatty acids in bio-oils has been achieved using room temperature, environmentally benign vortex fluidic flow chemistry.

Photoredox catalysis under shear using thin film vortex microfluidics

A microfluidic vortex fluidic device (VFD) operating in either confined or continuous mode is effective in high yielding photoredox reactions involving Rose Bengal, with short reaction times.

Stereospecific synthesis of resorcin[4]arenes and pyrogallol[4]arenes in dynamic thin films

Acid catalysed condensation of resorcinol and pyrogallol with aromatic aldehydes using a microfluidic vortex fluidic device (VFD) under continuous flow conditions results in the selective formation of resorcin[4]arenes and pyrogallol[4]arenes as predominantly their C(4v) isomers. Notably C(2v) isomers and C(2h) isomers can be also prepared with the latter being converted to the C(4v) isomer when the VFD operates in confined mode.

Simple and reusable picoinjector for liquid delivery via nanofluidics approach

Precise control of sample volume is one of the most important functions in lab-on-a-chip (LOC) systems, especially for chemical and biological reactions. The common approach used for liquid delivery involves the employment of capillaries and microstructures for generating a droplet which has a volume in the nanoliter or picoliter range. Here, we report a novel approach for constructing a picoinjector which is based on well-controlled electroosmotic (EO) flow to electrokinetically drive sample solutions. This picoinjector comprises an array of interconnected nanochannels for liquid delivery. Such technique for liquid delivery has the advantages of well-controlled sample volume and reusable nanofluidic chip, and it was reported for the first time. In the study of the pumping process for this picoinjector, the EO flow rate was determined by the intensity of the fluorescent probe. The influence of ion concentration in electrolyte solutions over the EO flow rate was also investigated and discussed. The application of this EO-driven picoinjector for chemical reactions was demonstrated by the reaction between Fluo-4 and calcium chloride with the reaction cycle controlled by the applied square waves of different duty cycles. The precision of our device can reach down to picoliter per second, which is much smaller than that of most existing technologies. This new approach, thus, opens further possibilities of adopting nanofluidics for well-controlled chemical reactions with particular applications in nanoparticle synthesis, bimolecular synthesis, drug delivery, and diagnostic testing.

PACS

85.85.+ j; 87.15.hj; 82.39.Wj.

Spinning up the polymorphs of calcium carbonate

Controlling the growth of the polymorphs of calcium carbonate is important in understanding the changing environmental conditions in the oceans. Aragonite is the main polymorph in the inner shells of marine organisms, and can be readily converted to calcite, which is the most stable polymorph of calcium carbonate. Both of these polymorphs are significantly more stable than vaterite, which is the other naturally occurring polymorph of calcium carbonate, and this is reflected in its limited distribution in nature. We have investigated the effect of high shear forces on the phase behaviour of calcium carbonate using a vortex fluidic device (VFD), with experimental parameters varied to explore calcium carbonate mineralisation. Variation of tilt angle, rotation speed and temperature allow for control over the size, shape and phase of the resulting calcium carbonate.

Continuous flow vortex fluidic production of biodiesel

Vortex fluidic synthesis of biodiesel from sunflower oil under continuous flow at room temperature, with spontaneous phase separation.