Zinc Oxide Superstructures in Colloidal Polymer Nanocomposite Films: Enhanced Antibacterial Activity through Slow Drying
Zinc Oxide Superstructures in Colloidal Polymer Nanocomposite Films: Enhanced Antibacterial Activity through Slow Drying
复制标题
DOI：
10.1021/acsapm.9b00991
复制
发表时间：
2020-02-01
影响因子：
5
通讯作者：
Martin-Fabiani, Ignacio
中科院分区：
文献类型：
--
作者：
Dong, Yichen;Argaiz, Maialen;Martin-Fabiani, Ignacio
控制杀菌剂在聚合物纳米复合材料薄膜厚度上的分布是开发高效抗菌表面的最大挑战之一。在此类应用中，关键是要最大限度地提高薄膜顶面的杀菌剂含量，以确保与细菌接触。在这里，我们利用蒸发驱动的胶体自组装来控制由聚合物和氧化锌（ZnO）纳米粒子的胶体混合物铸造的聚合物复合膜中杀菌剂的垂直分布。我们进行了一项彻底的研究，表明蒸发速率和 ZnO 体积分数对最终薄膜结构及其润湿和抗菌性能有很大影响。对于足够高的 ZnO 体积分数，ZnO 纳米粒子在薄膜顶部的上层结构中组装，所使用的蒸发速率越慢，上层结构越高，并且通过缓慢的薄膜干燥实现最大的 ZnO 表面覆盖。在高ZnO体积分数（.95 = 0.29）下，随着蒸发速率的降低，对大肠杆菌的抑制区域直径增大，在慢蒸发速率下形成的纳米复合膜具有最强的抗菌活性。我们提出了一种形成这些胶体超结构的模型，该模型基于干燥过程中大颗粒（聚合物）和小颗粒（ZnO）的分离，然后由于两个群体表面电荷的差异而将小颗粒聚集在堆积的大颗粒周围。我们的工作不仅为抗菌胶体薄膜的设计和组装提供了宝贵的指导，还为更广泛的功能性胶体聚合物薄膜（包括耐磨、自清洁等）的设计和组装提供了宝贵的指导。
Achieving control over the distribution of biocides across the thickness of polymer nanocomposite films is one of the largest challenges to develop efficient antibacterial surfaces. In such applications, it is key to maximize the biocide presence at the film top surface to ensure contact with bacteria. Here, we make use of evaporation driven colloidal self-assembly to control the vertical distribution of biocides in polymer composite films cast from colloidal blends of polymer and zinc oxide (ZnO) nanoparticles. We present a thorough study which shows that the evaporation rate and ZnO volume fraction have a strong impact on the final film architecture and on its wetting and antibacterial properties. For high enough ZnO volume fraction, the ZnO nanoparticles assemble in superstructures on top of the film, which are higher the slower the evaporation rate used, and maximum ZnO surface coverage achieved through slow film drying. At high ZnO volume fraction (.95 = 0.29), the zone of inhibition diameter against Escherichia coli increases as evaporation rate decreases, with the nanocomposite films having the strongest antibacterial activity when formed at slow evaporation rate. We propose a model for the formation of these colloidal superstructures based on the segregation of large (polymer) and small (ZnO) particles during drying, followed by the assembly of small particles around packed large particles due to differences in the surface charge of the two populations. Our work provides valuable guidelines for the design and assembly of not only antibacterial colloidal films but also a wider range of functional colloidal polymer films including abrasion resistant, self-cleaning, and others.