P1-0192 — Annual report 2015
1.
Thermooptical molecule sieve on the microscale

A combination of thermophoresis and fluid flow can be used to trap molecules and particles. We showed that heating by scanning motion of an elongated laser spot creates a strong thermal trap. Additionally, it induces a global fluid flow that feeds the trap. Such “thermal sieve” can accumulate molecules from a large surrounding region within seconds into a 10 μm spot. Numerical modeling gives a quantitative prediction of the effect. Traps can be dynamically created, relocated, and tuned, which can be used for particle sorting.

COBISS.SI-ID: 28423207
2.
Ion-specific self-assembly of a lipophilic guanosine derivative in thin surface films

We investigated effect of various ions on spontaneous organization of guanosine derivatives in Langmuir and Lagmuir-Blodgett (LB) films. The results show that, similar to solutions, also in thin films in particular potassium ions have very strong effect on molecular assembly. Already a relatively small addition of these ions causes structural transition from lamellar to mosaic structure.

COBISS.SI-ID: 2803812
3.
Viscoelastic properties of levan-DNA mixtures Important in microbial biofilm formation as determined by micro- and macrorheology

Viscoelastic properties of homogeneous and inhomogeneous levan-DNA mixtures were studied with optical tweezers and a rotational rheometer. Both macro- and micro-rheology measurements in homogeneous levan-DNA mixtures revealed pseudoplastic behaviour. In phase-separated levan-DNA mixtures, the results of macro- and microrheology differed significantly.

COBISS.SI-ID: 4506744
4.
Optical properties of aluminum nitride single crystals in the THz region

We measured the refractive indices and the absorption in bulk single crystals of aluminum nitride, in the region from 1 to 8 THz. Additionally, we estimated the static dielectric constants to be 7.84 and 9.22, for the ordinary and extraordinary polarization, respectively. Our results are relevant in considering this material for terahertz applications.

COBISS.SI-ID: 28838439
5.
Development and characterization of lanthanide-doped nanoparticles exhibiting upconversion fluorescence in aqueous suspensions

We have participated in interdisciplinary research of co-doped inorganic nanoparticles which exhibit upconversion fluorescence, e.g., Yb3+,Tm3+:NaYF4. Such nanoparticles have great potential for development of new techniques for diagnostics and therapy of cancer.

COBISS.SI-ID: 28445735