Naslov
Jumping Crystals - a case of 4-hydroxy-N'- isopropylidenebenzohydrazide

Autori
Željko Skoko, Željko ; Popović, Dean ; Popović, Jasminka ; Molčanov, Krešimir ; Popović, Stanko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstract of the 22nd Slo_cro Crystallographic Meeting / - , 2014

Skup
22nd Slo-Cro Crystallographic Meeting

Mjesto i datum
Logarska dolina, Slovenija, 16.06.2014. - 20.06.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
jumping crystals; thermosalient materials

Sažetak
Thermosalient materials, or colloquially commonly called “jumping crystals”, are promising materials for conversion of thermal (or light) energy to mechanical work on nanoscale [1]. These materials, when heated/cooled undergo a sudden and sharp polymorphic single crystal to single crystal phase transition. During this transition the crystals experience a change in their shape, as well as in the size of the unit-cell, and this change is so large that it causes them to jump up to height that is several times their size. This behaviour usually takes place in the time frame of several microseconds. Jumping crystals show high discontinuity in the change of the crystal lattice ; the change can be up to 12% [2]. It was reported [3] that 4-hydroxy-N’- isopropylidenebenzohydrazide shows behaviour somewhat similar to that of jumping crystal. This system was found in three polymorphic modifications (I, II and III), all having the same polar space group Pna21, with the phase transitions I to II, and III to II reported as topotactic (single crystal to single crystal). It was also reported that during irreversible phase transition from I to II, the polar axis undergoes a strong compression (approximately 15%) and single crystals of phase I are violently shuttered into single crystal fragments of the phase II (without jumping), while in the reversible phase transition III to II the polar axis expands (approximately 14%) and the integrity of the single crystals is preserved – and no movement of crystals is observed. Our measurements showed somewhat different behaviour – during the irreversible phase transition from I to II some of the crystals did indeed shutter into smaller fragments, but a large number remained intact and showed a typical jumping crystals behaviour – jumping all around over the large distances (several cm). This is typical of other thermosalient materials [1]. Also, during the reversible phase transition II <-> III (both ways) crystals exhibited jumping behaviour, alas somewhat weaker than during the phase transition I to II. This is in contrast to previously reported behaviour and the new model for jumping crystals phenomenon in this system has to be proposed. References: [1] Skoko, Ž., Zamir, S., Naumov, P. & Bernstein, J. (2010), J. Am. Chem. Soc. 132, 14191. [2] Steiner, T., Hinrichs, W. & Saenger, W. (1993), Acta Crystallogr. B49, 708. [3] Centore, R., Jazbinsek, M., Tuzi, A., Roviello, A., Capobianco, A. & Peluso, A. (2012) CrystEngComm 14, 2645.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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