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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Generally, the polymer structure formation process is governed by two main factors – the thermodynamics and kinetics. Sometimes the sample preparation conditions make the system to depart from equilibrium and to stay trapped in a transient state. As compared to atomic liquids, the relative sluggishness of polymer chains makes observation of metastable transient states much easier. Recent models suggest that their structural evolution pass via a transient LC state. In some cases, polymer samples prepared in extreme processing conditions contain a significant amount of such transient partially-ordered state (POS) at room temperature. The effect of the thermal history on the final materials structure of flexible-chain polymers can be generalized on Cooling-Transformation Diagram (CTD) (Figure 1a). The diagram helps to predict the final structure (amorphous, partially-ordered, metastable or stable crystalline phase) as a function of cooling rate. In the presented work the role of metastable state in structure formation process is illustrated on several examples. Particularly, the relationship between local ordering and electronic properties of conductive polymers was presented. In the work the unique approach of fabrication and study of thermophysical properties of metastable materials using nanocalorimetry in combination with microfocus X-ray diffraction will be discussed (Figure 1b-e). The concept of non-equilibrium partially-ordered states allows explaining the final polymorphic content in the material as a function of the formation kinetics. This method allows to fabricate the polymer materials with unusual structure and macroscopic properties.