3.5.4. XRD

X-ray diffraction ranging from 5◦ to 90◦ at 2θ values was applied to examine 7,8-DHF's physical state in different nanoparticles. As presented in (Figure 4E), 7,8-DHF was highly crystalline with multiple sharp diffraction peaks at the range of 5~40◦. On the one hand, when the diffraction angles of ALG in the 2θ range were 13.2◦ and 21.8◦, two flat peaks

without sharp diffraction maximum appeared in the XRD spectrum. On the other hand, CMC only had a flat peak at a diffraction angle of 20.2◦, while no sharp diffraction peaks were emerged. This XRD hump indicated that both pure polysaccharides were totally in an amorphous form [21,32]. However, no obvious sharp diffraction peaks about crystalline form for 7,8-DHF were found in both binary and ternary nanoparticles. Such behavior indicated 7,8-DHF was completely loaded into nanoparticles with an amorphous state. Interestingly, in comparison to DHF-S/Z, the hump for DHF-ALG/S/Z was distinctly increased, while the hump of DHF-CMC/S/Z was only slightly increased as the diffraction angle was at 19.6◦. Thus, the polysaccharide types applied to construct nanocomposites can significantly affect XRD patterns. Moreover, no characteristic peaks for these two polysaccharides were observed. Collectively, due to changes in the interactions (hydrophobic, hydrogen bonding, and electrostatic) among zein, polysaccharide, and surfactant molecule, distinguishable behaviors of 7,8-DHF in DHF-S/Z, DHF-CMC/S/Z, and DHF-ALG/S/Z were observed.
