RP 4: Heterogeneous ice nucleation induced by porous materials

Prof. Dr. Thomas Koop

Department of Chemistry, Bielefeld University

 

Assistance:  Dr. Carsten Budke (Post-Doc), Katharina Dreischmeier, Evelyn Jantsch

 

 

In the first phase of INUIT, RP4 focussed on the study of singular versus stochastic behaviour in heterogeneous ice nucleation. For this purpose a new experimental device capable of quantifying the role of time dependence in immersion freezing was to be developed. This goal has been achieved successfully with the realization of a novel optical freezing array BINARY (Bielefeld Ice Nucleation ARraY), see details in Budke and Koop 2015 . The BINARY device is optimized for the study of immersion mode ice nucleation in microliter-sized droplets in the temperature range down to -40 °C and at cooling rates between 0.1 and 10 °C min-1. BINARY allows for the simultaneous study of 36 droplets, all separated from each other in individual compartments.

 



Screenshot of an ice nucleation experiment with BINARY. Bright droplets are frozen, darker droplets are still liquid

 

For a full movie of this experiment, see:

 

 

 

With the BINARY technique established we will continue performing experiments on the time dependence in immersion freezing. Furthermore, during INUIT-2 the focus of RP4 will change towards studying ice nucleation induced by porous materials, i.e. studies of the ice nucleation activity of various porous materials as a function of material type, concentration, and average pore size as well as a comparison of the ice nucleating behaviour of flexible pores with that of rigid pores. Further tasks include investigations of the ice nucleation activity of reference aerosols shared within the INUIT consortium and that of natural dust samples in cooperation with Yinon Rudich from the Weizmann Institute, Israel, as part of a Mercator fellowship.


For more information see:  http://www.uni-bielefeld.de/chemie/koop/