Marinelli M, Mercuri F, Paoloni S, Zammit U
Dipartimento Ingegneria Meccanica, Universitá di Roma Tor Vergata, Rome, Italy.
Phys Rev Lett. 2005 Dec 2;95(23):237801. doi: 10.1103/PhysRevLett.95.237801. Epub 2005 Nov 29.
By means of specific heat spectroscopy, we have studied the dynamics of nematic 8CB nucleated, in the presence of random disorder, as the temperature is lowered across the isotropic to nematic phase transition such that the crossover region of random dilution to random field regimes of disorder strength is explored. We show, in terms of frequency dependence, hysteretic behavior, and aging effects, that the out-of-equilibrium properties of the nematic nucleated in the random disorder regime are strongly reminiscent of the bulk material while the one grown in the random field regime shows a glassy behavior with aging leading to slower dynamics. The aging effect has been explained in terms of strain relaxation in analogy with observations in other soft glassy colloidal systems.
通过比热光谱法，我们研究了在随机无序存在的情况下，向列型8CB在温度降低通过各向同性到向列相转变时的成核动力学，从而探索了无序强度从随机稀释到随机场区域的交叉区域。我们从频率依赖性、滞后行为和老化效应方面表明，在随机无序区域中成核的向列相的非平衡性质与块状材料非常相似，而在随机场区域中生长的向列相则表现出玻璃态行为，老化导致动力学变慢。老化效应已根据应变弛豫进行了解释，这与在其他软玻璃态胶体系统中的观察结果类似。
