Biomolecules and nanostructures
The Optical Sciences group studies the interaction of light and matter at the nanoscale.
We do this by exploring ways to shape light and its environment. It's what we call
active and passive control. Our current focus is on the interaction of light with
biomolecules and nanostructures. We are part of Twente
University's Department of Science and Technology and member of the
Supramolecular materials: Molecular packing of tetranitrotetrapropoxycalixarene in highly stable films with second-order nonlinear optical properties
Kenis PJA, Noordman OFJ, Schonherr H, Kerver EG, Snellink-Ruel BHM, van Hummel GJ, Harkema S, van der Vorst CPJM, Hare J, Picken SJ, Engbersen JFJ, van Hulst NF, Vancso GJ, Reinhoudt DN
CHEMISTRY-A EUROPEAN JOURNAL
vol 4 issue 7: p1225-p1234 JUL 1998
Highly stable films of tetranitrotetrapropoxycalixarene (9) with second-order nonlinear optical (NLO) properties and a noncentrosymmetric structure were obtained by a novel crystallization process at 130-140 degrees C in a de electric field. The packing of 9 in these films was elucidated by a combination of X-ray diffraction, angle-dependent second- harmonic generation, and scanning force microscopy (SFM). The experimental results agree well with solid-state molecular dynamics calculations for these films. No crystalline phase was observed for nitrocalixarene derivatives with longer or branched alkyl chains; this explains the limited NLO stability of films of these calixarenes. Scanning force microscopy on the aligned films of 9 showed two distinct surface lattice structures: a rectangular lattice (a = 9.3, b = 11.7 Angstrom) and a pseudohexagonal lattice (d approximate to 11.4 Angstrom). The combination of these data with the interlayer distance of 8.9 Angstrom (X-ray diffraction) allowed the packing of molecules of 9 in these structures to be fully elucidated at the molecular level.