Photoregulation of molecular assembly in thin surface filmsLičen, Matjaž (Avtor) Drevenšek Olenik, Irena (Mentor) DNA nucleotidesphotoisomerizationazobenzeneLangmuir filmsLangmuir-Blodgett filmshydrogen bondingThe versatility and many appealing properties of DNA nucleobase derivatives have made them the target of investigations for use in a wide range of possible applications: from medicine to novel materials for nanotechnology and biocompatible electronics. By modifying a nucleobase with a photoactive moiety, one is able to control the binding between nucleobases by irradiating the molecules with light of specific wavelengths. In this doctoral thesis, I present the results of the studies of the behaviour of three azo-functionalised guanosine derivatives in thin surface films at the air-water interface and after transfer to solid substrates by using the Langmuir-Blodgett method. Even though the studied molecules did not possess a typical amphiphilic structure, we found that all of them formed sufficiently stable films at the air-water interface. Furthermore, optical irradiation induced changes in the measured properties of the films, and could be used to reversibly switch the films from one state to the other using two different wavelengths of light. Finally, a phenomenological model was developed to describe the time dependence of surface pressure in a Langmuir film during irradiation with actinic light. Using this model, we were able to show that the behaviour of a mixed guanosine–cytidine film during irradiation was consistent with photoinduced inhibition of hydrogen bonds.20202020-06-24 08:15:02Doktorsko delo/naloga117099sl