Mulkerns Niall M C, Hoffmann William H, Ramos-Soriano Javier, de la Cruz Noelia, Garcia-Millan Teodoro, Harniman Robert L, Lindsay Ian D, Seddon Annela M, Galan M Carmen, Gersen Henkjan
H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK.
Bristol Centre for Functional Nanomaterials, University of Bristol, Bristol, BS8 1TL, UK.
Nanoscale. 2022 Jun 9;14(22):8145-8152. doi: 10.1039/d2nr00120a.
Direct measurements to determine the degree of surface coverage of nanoparticles by functional moieties are rare, with current strategies requiring a high level of expertise and expensive equipment. Here, a practical method to determine the ratio of the volume of the functionalisation layer to the particle volume based on measuring the refractive index of nanoparticles in suspension is proposed. As a proof of concept, this technique is applied to poly(methyl methacrylate) (PMMA) nanoparticles and semicrystalline carbon dots functionalised with different surface moieties, yielding refractive indices that are commensurate to those from previous literature and Mie theory. In doing so, it is demonstrated that this technique is able to optically detect differences in surface functionalisation or composition of nanometre-sized particles. This non-destructive and rapid method is well-suited for industrial particle characterisation and biological applications.
直接测量功能部分对纳米颗粒的表面覆盖程度的方法很少见，目前的策略需要高水平的专业知识和昂贵的设备。在此，提出了一种基于测量悬浮液中纳米颗粒的折射率来确定功能化层体积与颗粒体积之比的实用方法。作为概念验证，该技术应用于用不同表面部分功能化的聚甲基丙烯酸甲酯（PMMA）纳米颗粒和半结晶碳点，得到的折射率与先前文献和米氏理论中的折射率相当。通过这样做，证明了该技术能够光学检测纳米级颗粒表面功能化或组成的差异。这种无损且快速的方法非常适合工业颗粒表征和生物应用。
