Acrobatics of molecular crystals – thermosalient materials for new generation of actuators

Duration of the project: 01.07.2015.-30.06.2018

Targeted design of new actuating materials which are capable of fast, reversible and controllable mechanical motion in response to external stimuli (thermal or light) is at the frontier of the contemporary materials science research. Among these, the few serendipitiously discovered examples of crystals that suddenly jump while heated, to distances several thousand times larger than their own dimension in less than 1 ms, provide the most impressive display of the conversion of thermal energy into mechanical work. These thermosalient crystals are biomimetic, nonpolymeric self-actuators par excellence. Yet, due to exclusivity and individuality of the phenomenon, but alse due to the complexity of analytical methods for its characterization, reasons behind this colossal self-actuation remain unexplained.

With the aim of final elucidation of the thermosalient phenomenon, this project represents first systematic attempt to disentangle the interplay between the thermodynamic, kinematic, structural and macroscopic factors that drive the thermosalient effect by employing various diffraction (XRD), microscopic (hot stage), spectroscopic, (FTIR, UV/VIS) and thermal (DTA/DSC/TG) techniques. Systems under study will also be investigated by the means of quantomechanical modeling (DFT). Finally, never mentioned in the literature so far, results of the experimental methods will be combined with the results of quantomechanical modeling of this visually very attractive, and potentially very useful, effect. With this, the final punch will be delivered to this riddle and the absolute elucidation of the thermosalient effect will enable targeted fabrication of thermosalient actuators.

Members of the project team

  1. Lidija Androš

  2. Vito Despoja

  3. José Fernandes

  4. Teodoro Klaser

  5. Panče Naumov

  6. Željko Skoko (PI)

  7. Zoran Štefanić

This work is financed by the Croatian Science Foundation project IP-2014-09-7506

Latest info (in the past 24 months):

  1. -September 2016: Željko Skoko held a plenary lecture at 24th Croatian - Slovenian Crystallographic Meeting, Bol, Hrvatska

  2. -October 2016:  Teodoro Klaser joined our group as the CSF PhD student

  3. -December 2016: Igor Đerđ presented results of our investigtations at 14th Conference of the Asian Crystallographic Association, Hanoi, Vietnam

- February 2017: José Fernandes joined our group as a postdoc fellow

  1. -March 2017: Jasminka Popović gave an invited talk on thermosalient materials at the Hong Kong University, Hong Kong

  2. -April 2017: Željko Skoko gave a talk and presented latest results of our studies at British Crystallographic Association Spring Meeting, Lancaster, UK

  3. -April 2017: Jasminka Popović  held an invited lecture at the meeting Contemporary Crystallography in Croatia, Poreč, Hrvatska

  4. -June 2017: Jasminka Popović held a talk at The 6th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies, Fukui, Japan

  5. -June 2017: José Fernandez held a lecture and presented his work within the scope of the project at 25th Slovenian-Crystallographic Meeting, Ljubljana, Slovenia

  6. -June 2017: Teodoro Klaser gave a talk at 25th Slovenian-Crystallographic Meeting, Ljubljana, Slovenia

  7. -June 2017: Željko Rapljenović i Luka Vanjur received a Rector’s award for their work “When molecular crystals perform acrobatics - example of Oxitropium bromide and Scolopamine methyl bromide”

  8. -August 2017: Željko Skoko held an invited talk at the IUCR (International Union of Crystallography) Congress at Hyderabad, India

  9. -Teodoro Klaser held a poster presentation titled „Nanoworld of acrobatic crystals – thermosalient effect (example of Scopolamine bromide)“ at the 13 th Multinational Congress on Microscopy which was held from 24. to 29. September 2017. in Rovinj.

  10. -Teodoro Klaser held an invited lecture titled „Thermosalient mystery“ at the 25 th Inernational Scientific Meeting on Vacuum Science and Techniqe which was held from 17. to 18. May 2018. at Gozd Martuljak (Slovenia).

  11. -José Fernandes presented a talk titled „Thermosalient Behavior on the Dehydration of Scopolamine Bromide Hydrate“ at the 26 th Croatian-Slovenian Crystallographic Meeting which was held from 13. to 17. June in Poreč.

  12. -Teodoro Klaser presented a talk titled „Is the thermosalient effect without phase transition possible?“ at the 26 th Croatian-Slovenian Crystallographic Meeting which was held from 13. to 17. June in Poreč.


  1. -Paper was published in Crystal Growth&Design describing for  the first time ever thermosalient effect by theoretical calculations (DFT): link

  2. -Paper was published in Crystals presenting for the first time thermosalient effect without the phase transition: link