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.

We investigated the optical properties of localized surface plasmons with different orders in individual silver nanotriangles with different sizes by electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) in the same scanning transmission electron microscope. EELS and CL spectral imaging within the same nanotriangles give information about the extinction and scattering from the nanostructures. As measured from both techniques, the first two order modes showed similar spatial distributions. However, the appearances of slightly different resonant energies were confirmed in both lower and higher order plasmon modes. For the first two lower order modes, the resonant energy in CL was blue-shifted compared to that in EELS, which can be understood in a simple damped oscillator picture. This confirms the experimental and theoretical observations recently made on dipolar plasmons in gold. It also extends it to the second-order modes. The next higher order modes exhibit an apparent inverted shift, which could not fit in such a picture. On the basis of boundary element methods numerical simulations, we interpret this apparent inversion of shift as a combined effect of (1) the spectral mixing of higher order modes and (2) the change in the relative weights of higher order modes between both spectroscopy techniques, i.e., the much faster drop in higher order mode intensity in CL compared to EELS. Both effects are enhanced by the large damping in these imperfect, lithographed structures.