Preparation of Nano-Sized Zinc Oxide in Amphiphilic Polymer Gel Network and Evaluation of Luminescence Properties

纳米氧化锌（ZnO）颗粒具有量子尺寸效应，其发光强度和波长依赖于颗粒尺寸。纳米氧化锌的制备方法一直是人们研究的热点。然而，纳米颗粒容易生长或聚集，并失去纳米颗粒的性能。本研究提出了在聚合物凝胶网络中制备纳米ZnO粒子的方法，并考察了凝胶的制备组成对所形成的纳米ZnO粒子在凝胶中的稳定性的改善和对粒径的控制能力，所用的凝胶是绝对透明的两亲性N，N-二甲基丙烯酰胺凝胶。以乙醇为溶剂，采用自由基聚合法合成了凝胶，并以不同交联剂含量制备了厚度为2 mm的平板型凝胶。通过测量探针分子尺寸与截留效率之间的关系来评估有效网络尺寸。聚乙烯 ...更多信息 使用各种分子量的二醇作为探针分子。纳米ZnO的制备包括两个步骤：（1）以乙酸锌和乙醇为原料，在80℃下反应3 h制备前驱体;（2）前驱体与氧化锂在超声浴中水解。在凝胶中纳米尺寸的ZnO颗粒的制备中，干燥的凝胶在含有所需量的乙酸锌的乙醇中溶胀。在<onset>50℃时，ZnO胶体的吸收光谱的起始波长（λ）随时间向长波方向移动，这与ZnO的粒径有关。胶体变得不透明，并在2天内观察到沉淀。另一方面，<onset>在凝胶中制备的ZnO颗粒的λ在一个月内几乎没有变化，并且凝胶是绝对透明的。λ_（max<onset>）取决于凝胶剂的组成，交联剂的浓度。这些结果表明，在凝胶中形成的纳米尺寸的ZnO颗粒是非常稳定的，并且可以通过凝胶的交联密度来控制颗粒尺寸。少

Nano-sized zinc oxide (ZnO) particles show the quantum size effect, and the luminescence intensity and wavelength depend on the particle size. The preparartion methods of nano-sized ZnO particles have been investigated actively. However, nano-particles grow or aggregate easily, and lose the properties of nano particles. In this study, the preparation of nano-sized ZnO particles in the polymer gel network was proposed, and the improvement of the stability of formed nano-sized ZnO particles in the gel and the capability of the control of particle size by the preparation composition of gel were examined.Amphiphilic N,N-dimethylacrylamide gel which are absolutely transparent was used. The gel was synthesized by a radical polymerization in ethanol, and the plate type gels of 2 mm thickness were prepared with various conmpositions of cross-linker. The effective network size was evaluated by measuring the relationship between the probe molecular size and the rejection efficiency. Polyethylene … More glycols of various molecular weights were used as the probe molecules. The preparation of nano-sized ZnO particles consists of the following two steps : (1)preparation of precursor by reacting zinc acetate with ethanol at 80℃ for 3 hours and (2)hydrolysis of the precursor with lithium oxide in a ultra-sonic bath. In the preparation of nano-sized ZnO particles in the gel, the dried gel was swollen in ethanol containing the desired amount of zinc acetate. The subsequent procedures were same as those mentioned above.The onset wavelength (λ_<onset>) of the absorption spectrum of ZnO colloid which is related to the particle size shifted to longer wavelength with time at 50℃. The colloid became opaque and the precipitate was observed within 2 days. On the other hand, the λ_<onset> of ZnO particles prepared in the gels scarcely changed over one month, and the gel was absolutely transparent. The λ_<onset> depended on the preparation composition of gel, i.e., the concentration of cross-linker. These results suggest that nano-sized ZnO particles formed in the gel are extremely stable and that the particle size can be controlled by the cross-linking density of gel. Less