engleski

Some relevant results from electrical analysis of thermosalient crystals of 1,2,4,5- tetrabromobenzene and 1,2,4,5-tetraclorobenzene

Thermosalient materials, or more colloquially called jumping crystals, are a class of materials that exhibit mechanical motion as a response to the thermal stimulus. Such materials, which are capable of extremely fast and, more important, controllable energy conversion are extremely important candidates for active actuating elements, such as flexible electronic switches, displays, artificial muscles, microfluidic valves and gates, heat sensors etc. Synthetized crystals of molecular alloys, with different concentrations of 1, 2, 4, 5- tetrabromobenzene and 1, 2, 4, 5-tetraclorobenzene, were studied with hot stage microscope to characterize the thermosalient behavior of these mixed crystals. Resulting analysis shows that a threshold concentration for the activation of the jumping of crystals is present and that there is a dependency of the temperature, at which phase transition occurs, on the concentration of the mixture. The temperature of the thermosalient phase transition can be fine-tuned in the interval of 10 K which presents a giant step towards the practical utilization of this effect. On this system a preliminary spectroscopic impedance analysis was performed, and several interesting new information emerged about electric properties of thermosalient materials, showing that this kind of analysis could provide new important information about crystal jumping and how to electrically control the activation of “jumping”.

Thermosalient materials ; phase transition ; thermal expansion ; electric properties

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