使用可生物降解的羧甲基纤维素(CMC)和 Eu 3 + 络合反应，在不同的 pH 值下制备了 CMC/Eu 纳米络合粒子．FT- IR结果证实 CMC 链上的羧基、未被取代的羟基中的氧原子及醚键的氧原子均参与了与 Eu 3 + 的反应;SEM 及 TEM 结果表明，所合成的 CMC/Eu络合物是纳米级的，并呈现较弱的多晶型结构;固态紫外吸收光谱表明，CMC 是一个良好的能量供体和荧光敏化剂．产物的粒径及其分布与粒子荧光性质间具有依赖关系．pH =7时，所制备的产物的粒径最小(150 ～200nm)、分布最均匀，其荧光强度最强，荧光单色性也高;随着 pH 值的增大，粒子团聚加剧，产物的粒径增大，其荧光强度相应减弱，这一结果体现了量子尺寸效应．

In this paper,CMC/Eu complex nanoparticles were synthesized at different pH values by the reaction of Eu 3 + and biodegradable carboxymethyl cellulose (CMC). FT- IR results confirm that the carboxyl groups on CMCchains,the oxygen atoms of unsubstituted hydroxyl groups and the oxygen atoms of ether bonds all involve in thereaction with Eu 3 + .SEM and TEM results show that the synthesized CMC/Eu particles are in a nanoscale andpresent weak polycrystalline structure.Solid UV- Vis absorption spectra show that CMC is a good energy donor andfluorescent sensitizer.Moreover,it is found that there is a strong dependence of particle size and distribution on thefluorescence properties of CMC/Eu nanoparticles,and that pH value greatly affects the particle size,the particlesize distribution and the fluorescence properties; for instance,the sample synthesized at pH 7 is of the smallest par-ticle size (150 ～200nm),the most uniform size distribution,the strongest fluorescence intensity and high fluores-cence monochromaticity,and,with the increase of pH value,the nanoparticles aggregate more seriously,the particlesize increases,and the fluorescence intensity accordingly reduces.All these findings reflect the quantum size effect.