Observation of the Transient Rotator Phase ofn-Hexadecane in Emulsified Droplets with Time-Resolved Two-Dimensional Small- and Wide-Angle X-Ray Scattering

Abstract

Crystallization of n-hexadecane in emulsion droplets was studied using time-resolved two-dimensional small- and wide-angle x-ray scattering with differential scanning calorimetry (2D-SAXS-WAXS-in situ DSC) which provides information about both nano- and subnanoscale structural change. n-hexadecane in droplets reproducibly crystallized into the stable triclinic phase via a transient-rotator phase. This is in contrast with previous results that the rotator phase of n-hexadecane was observed only occasionally for bulk samples. Thus we confirmed the existence of rotator phase in n-hexadecane, which is important for the study of crystallization of soft materials. We suggest that the rotator phase at the interface of oil and water plays a precursor role for bulk crystallization. This study demonstrates that 2D-SAXS-WAXS-in situ DSC is a powerful tool for the study of a transient phase.

Poisson’s ratio of orientationally disordered hard dumbbell crystal in three dimensions

“…In such a phase, sometimes referred to as a plastic crystal, average positions of molecular centers of mass form a periodic structure, while orientations of particles are not periodic. The rotator phase was experimentally observed both in organic [3,4] and inorganic [5] compounds. Studies of this phase allow one to better understand the crystallization process in soft materials [4] and the phenomena of ionic transport [5,6].…”

“…The rotator phase was experimentally observed both in organic [3,4] and inorganic [5] compounds. Studies of this phase allow one to better understand the crystallization process in soft materials [4] and the phenomena of ionic transport [5,6]. It should be stressed that the existence of various solid phases is not restricted to complex, polyatomic molecules.…”

Uniform discotic wax particles via electrospray emulsification

“…They are also good model systems to investigate crystal nucleation and the growth of hydrocarbons, polymers, surfactants, and lipids [8][9][10][11].…”

A combined small- and wide-angle x-ray scattering detector for measurements on reactive systems

“…CCD detectors are widely used to record small-and wide-angle x-ray scattering in lab-based or synchrotron-based experiments. [24][25][26] A CCD detector with a time resolution down to a millisecond (or milliseconds) has been used to perform SAXS and WAXS experiments. 27 The PILATUS detector is a two-dimensional detector which is a hybrid pixel detector operating in single-photon-counting mode with a readout time of less than 3 ms and a frame rate of 200 Hz.…”