Crystallinity of Eu-doped Poly(L-lactic acid) Microspheres by Emulsification

This study explores a novel approach to regulate the crystallinity of PLA microspheres by emulsification. Through powder and grazing incidence X-ray diffraction with synchrotron radiation, together with calorimetric and spectroscopic analyses, it has been observed that poly(L-lactic acid) (PLLA) microspheres, whether pure or doped with europium, exhibit an adjustable crystalline fraction achieved through emulsification at temperatures ranging from 20 to 80°C. Specifically, the pure PLLA microspheres show a range from 16% to 35%, while the doped ones from 30% to 50%. Significantly, a comprehensive analysis, comparing macro- and micro-analysis, supports a model in which emulsification temperature influences the ratio of amorphous to α-phase crystalline components within each PLLA microsphere. Additionally, unlike bulk material, the microspheres exhibit no infrared-active changes in the molecular unit after exposure to X-rays. These results pave the way for innovative strategies to produce radiation-resistant microspheres with controlled crystallinity.