In the present investigation, the crystallization and phase transition behaviours of normal alkane (n-docosane) in microcapsules with a mean diameter of 3.6 μm were studied by the combination of differential scanning calorimetry (DSC), temperature-dependent X-ray diffraction (XRD) and variable-temperature solid-state nuclear magnetic resonance (VT solid-state 13C NMR). The DSC and VT solid-state 13C NMR results reveal that a surface freezing monolayer is formed prior to the bulk crystallization of the microencapsulated n-docosane. More interestingly, it is confirmed that after the bulk crystallization, the ordered triclinic phase coexists with the rotator phase I (RI) for the microencapsulated n-docosane. We argue that the reduction of the free energy difference between the two phases, resulting from the microencapsulation process, leads to the coexistence of the ordered triclinic and rotator phases of the normal alkanes.
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