Fabrication of poly(p-oxycinnamoyl) nano-scale particles

Fabrication of poly(p-oxycinnamoyl) (POC) nano-scale particles was examined by using self-seeding polymerization of (E)-4-acetoxycinnamic acid in liquid paraffin. The diameter of the POC spheres was very susceptible to the polymerization temperature and the temperature drop was very efficient to control the nucleation process by the adjustment of the degree of super saturation leading to the decrease in the diameter. The average diameter of the spheres prepared at 320°C was 3.6 μm, whereas, the temperature drop from 320°C to 250°C just before the nucleation afforded the POC microspheres having average diameter of 2.2 μm. In order to prepare the nano-scale particles, only the self-seeding polymerization was not sufficient and the control of the growth process was additionally required. The POC particles having 600 nm of the average diameter were obtained by not only the temperature change from 320°C to 250°C and then 320°C but also the addition of 4-octadecyloxybiphenyl as a coalescence inhibitor. The average diameter was in nano-scale, but the diameter distribution became broader with bimodality.