Nanooptics and photonics 

P(VDF-TrFe) films for harmonic nanoparticles characterization

Ilchenko S.G.1, Multian V. V.2, Lymarenko R.A.1, Taranenko V.B.1,
Pullano S.A.3, Fiorillo A.S.3, Gayvoronsky V. Ya.2 
1 International Center “Institute of Applied Optics” National Academy of Science of Ukraine10G Kudryavska street, Kyiv, 04053, Ukraine.
E-mail: Svitlana-ilchenko@ukr.net
2 Institute of Physics NAS of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine
3 Department of Health Sciences University Magna Græcia Catanzaro, 88100, Italy

Poly(vinylidenefluoride-co-trifluoroethylene) P(VDF-TrFE) copolymer with chemical formula (CH2-CFH)n is optically transparent, semi-crystalline piezoelectric polymer, which mainly used in areas requiring excellent chemical resistance, high optical purity and excellent mechanical properties. 
Nonlinear optical properties of PVDF and its copolymer P(VDF-TrFe) film, for implementing in interface scanning technique, which allows investigate of different nanoparticles, gases, biological agents, mitochondria, etc., were researched. In general, such agents can demonstrate effect of sticking to the walls of cuvette. One of alternative solution for such issue can be using laser system, with flow cell what allows to obtain new volume of investigated material. In such configuration, there is a region under illumination with high intensity laser pumping, where liquid renews.
In this work we used P(VDF-TrFe) - transparent, chemical stable, flexible polymer as protecting layer of windows of cuvette for investigation of ZnO harmonic nanoparticles by interface scanning technique. Harmonic nanoparticles (HNPs) are a new type of nonlinear optical markers for biological systems based on inorganic oxide nanocrystals, with a noncentrosymmetric lattice that effectively converts a frequency of laser radiation. For this purpose, a specific flow cell was designed, where one of the windows is coated by P(VDF-TrFe).
The comparison of the sticking effect manifestation from different concentrations of ZnO HNPs colloidal suspension was done. It was shown that surface coated by P(VDF-TrFe) demonstrates minimal effect of HNPs sticking in wide range of concentrations and high efficiency in prolonged measurements.
Due to this effect and its mechanical, electrical, thermal, chemical resistance polymer can be used as coating layer of the cuvette for investigation of the biologically-active agent.