Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Nov;82(1):140-5. doi: 10.1016/j.saa.2011.07.024. Epub 2011 Jul 18.
Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO(3) contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO(3) concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.
胶乳纳米银颗粒是通过一种简单的绿色方法合成的，该方法利用硝酸银和天然橡胶胶乳（NRL）水溶液的热处理，从巴西橡胶树中提取。紫外-可见光谱检测到约 435nm 的特征表面等离子体吸收带。反应介质中的 NRL 和 AgNO3 含量都对 Ag 纳米颗粒的形成有影响。较低的 AgNO3 浓度导致粒径减小。银纳米颗粒的直径范围为 2nm 至 100nm，呈球形。选区电子衍射（SAED）图谱表明，银纳米颗粒具有面心立方（fcc）晶体结构。FTIR 光谱表明，银离子的还原是通过其与氨中的胺基相互作用而促进的，氨用于 NRL 的保存，而颗粒的稳定性则是由于顺式异戊二烯结合在纳米颗粒表面上。因此，从巴西橡胶树中提取的天然橡胶胶乳可以用作制备稳定的银纳米颗粒水相分散体的分散剂和/或稳定剂。此外，该工作提供了一种简单、易于操作、无污染且廉价的银纳米颗粒合成新方法。
