Newly discovered thermosalient effect in Triphenyltetrazolium chloride

Termoodskočni materijali proučavaju se više od 30 godina ne samo zbog znanstvenog i industrijskog potencijala, nego i svoje atraktivne i tajanstvene prirode. Kako samo ime govori, termoodskočni materijali su kristali kojih pri grijanju ili hlađenju dolazi do faznog prijelaza koji je toliko ekstremno brz i energičan da kristali odskakuju sa podloge na udaljenosti koje su višestruko veće od njihovih dimenzija. Uz sami termoodskočni (TO) efekt, postoje i popratne pojave koje su karakteristične tim materijalima kao što je negativna termička ekspanzija. U ovom se radu pokazuje novootkriveni termoodskočni efekt kod 8 različitih spojeva a istražuje se u materijalu triphenyltetrazolij kloridu (TTC) i pokazuju se okolnosti pri kojima se pojavljuje. U tu svrhu korištene su sljedeće eksperimentalne i računalne metode: rendgenska difrakcija u polikristalu, mikroskopija sa grijaćom pločom, diferencijalna pretražna kalorimetrija, računalni software X’Pert Highscore Plus (u svrhu analize difrakcijskih mjerenja) i drugi alati za statističku obradu podataka i grafičku obradu slika. Napravljeno je cjelokupno istraživanje u temperaturnom intervalu od -186° C do temperature tališta od 250° C kako bi se stvorila potpuna slika o prisutnom TO efektu. Ispitani su brojni uzorci od kojih su neki rekristalizirani u 3 različita otapala: vodi, acetonu i etanolu i uočeno je bogato “ponašanje” navedenog spoja: čak pet različitih temperaturnih intervala “skakanja”, pojava negativne termičke ekspanzije, polimorfizam i šest različitih faza iznad i ispod sobne temperature. Također je opažena histereza temperature TO efekta prilikom grijanja i hlađenja.Thermosalient materials are being studied for more than 30 years, not just for its scientific and industrial potential, but because of its attractive and mysterious nature. As the name says, thermosalient or “jumping” materials are crystals which when heated or cooled down undergo a phase transition which is so sudden and energetic that they jump off up to distances several times larger than their dimensions. Thermosalient effect is usually accompanied with other specific phenomena such as negative thermal expansion. In this work thermosalient effect is demonstrated for the first time in 8 different materials with special attention given to Triphenyltetrazolium Chloride (TTC) and circumstances under which it occurs are shown. For this purpose different experimental and computational methods such as powder x-ray diffraction (PXRD), hot stage microscopy, differential scanning calorimetry, X‘Pert Highscore Plus (for analysis of diffraction measurements) computer software and other tools for statistical data processing and graphical image processing were used. The entire study was performed at a temperature range of -186° C to the melting point of 250° C to fully characterize TO effect in this system. Numerous samples were tested, some of which were recrystallized from 3 different solvents: water, acetone and ethanol, and the rich “behaviour” of the titled compound was observed. As many as five different temperature intervals of jumping, the appearance of negative thermal expansion polymorphism and six different phases above and below room temperature. Hysteresis of the temperature of TO effect was also observed