2.6.3 Morphology and polymorphism
The morphology of oleogels and emulgels were characterized using polarized light microscopy by observing the crystalline microstructure of samples (Willett & Akoh, 2019). An Olympus BX40 microscope (Olympus America, Center Valley, PA, USA) was used at magnifications of 40, 100, 200, and 400x. Preparation of microscope slides consisted of heating samples to 60 °C and adding 1 drop of melted sample between a stationary and moving glass plate. The samples were then crystallized by storing at 4 °C overnight. Images were captured using an iDu Optics® LabCam (iDu Optics, New York, NY, USA) with an attached iPhone 6S (Apple, Cupertino, CA, USA), and examined with ImageJ software (National Institute of Health, LOCI, University of Wisconsin). All micrographs were taken in triplicate.
The polymorphism of samples was determined using X-ray diffraction (XRD) with a Bruker D8 Advance X-ray powder diffractometer (Billerica, MA, USA). Samples were first annealed with parameters set forth elsewhere (Willett & Akoh, 2019). Annealed samples were stored at -80 °C until analysis. XRD operating conditions included Co Kα radiation (λ = 1.79037 Å), voltage 35 kV, amperage 40 mA, scanning rate of 0.2° s−1, and a diffraction angle (2θ) range from 10 – 40°. Samples were analyzed in triplicate and short d-spacings (Å) of the crystalline structures were determined using EVA-diffraction software (Billerica, MA, USA).