Chemistry in microchips

Lab-on-a-chip systems are valuable tools to study chemical reactions. Microreactors offer a unique environment where reactions are carried out in micro- to nanoliter reaction volumes, thereby profiting from a large surface-to-volume ratio available and the fast diffusive mixing under laminar flow regimes. The continuous flow operating mode and the on-line monitoring offer high throughput possibilities, which make lab-on-a-chip systems unique compared to lab-scale experiments.

Within the MnF group the research is mainly focused on the study of a variety of chemical reactions and supramolecular interactions in microchips. A special topic is the study of reactions under high pressure. Different types of (inner wall modified) microchips are being used. The design and fabrication of sophisticated chips takes place in close collaboration with the group of Prof. Dr. J.G.E. Gardeniers of the University of Twente. Special attention is paid to the development of methods to characterize the reaction products both off-line and on-line with mass spectrometry, UV and 1H NMR spectroscopy. A real challenge is to find whether there is a relationship between the data obtained on chip and with lab scale. At the end a toolbox with different types of microchips will be obtained which can be used for a variety of chemical reactions.

Researchers involved:W. Bula, F. Costantini, R.J.M. Egberink, D.J. Joe

Microreactors on a chip

Figure 1.

Development of specific receptors

Already for a long time the group is involved in the design and synthesis of receptors for anions, cations, and neutral molecules. Our classical approach is the bringing together of ligating sites on a molecular platform (e.g. calixarenes and cavitands) giving rise to enhanced binding properties. Another approach is the controlled combination of molecular building blocks to receptors and capsules under conditions of thermodynamic control via e.g. hydrogen bond formation.

Currently, projects are ongoing for the development of receptors for actinide/lanthanide separation, a worldwide problem. It is of utmost importance to separate long living radioactive actinides from shorter living lanthanides in nuclear waste streams. Along several lines new potential ionophores are developed. Recently a new combinatorial approach has been developed for the design of novel types of ionophores.

Originally, in supramolecular chemistry most complexation studies are performed in solvents such as chloroform, acetonitrile, etc. However, in another project the formation and complexation behavior of supramolecular capsules is studied in water as a solvent.

Researchers involved: H. Dam, Vacancy

Electro-optic chromophores

In optical communication systems, electro-optic (EO) modulators are used to encode electrical input data signals into fiber optic transmission lines. The dominant EO material in the presently applied technology is lithium niobate. The present EO chromophores have several disadvantages such as photochemical degradation and anti-parallel clustering. The objective of our project is the development of novel types of EO chromophores by combining several donor-π-acceptor systems within one molecule; if possible this will be performed using hydrogen bonded systems. Another approach involves the preparation of EO polymers containing EO active rotaxanes, in which the chromophore is partly encapsulated in the cavity of a macrocycle.

Researcher involved: M. Faccini