带有铵或磺酸基团的有机磷表面官能化制备的表面带电氧化锆纳米粒子,Langmuir

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带有铵或磺酸基团的有机磷表面官能化制备的表面带电氧化锆纳米粒子
Langmuir ( IF 3.7 ) Pub Date : 2019-08-08 00:00:00 , DOI: 10.1021/acs.langmuir.9b01093
Charlotte Heinrich ₁ , Lucas Niedner ₁ , Bastian Oberhausen ₁ , Guido Kickelbick ₁

Affiliation

合成带有永久带电官能团（阳离子季铵盐或阴离子磺酸盐）的有机磷偶联剂，并将其用于直径小于10 nm的氧化锆纳米粒子的改性。通过FTIR和固态NMR光谱确认了表面官能化。表面覆盖率高达2.3–2.4分子/ nm ²通过使用这些带电偶联剂进行修饰，获得了优异的收率。均质改性颗粒的pH依赖性电荷测量结果显示，在铵盐和磺酸盐官能化的颗粒中，pH值在很宽的范围内均具有稳定的表面电荷。与带电的偶联分子和不带电的甲基膦酸共官能化的颗粒的表面电荷测量结果显示，随着不带电的偶联剂数量的增加，电荷密度降低。因此，通过在颗粒表面上通过共官能化来调节电荷。这样形成的表面带电胶体在第二步骤中用于逐层工艺所需的静电驱动的聚集现象。磺酸盐改性的带负电的SiO ₂用铵改性的ZrO ₂纳米粒子修饰直径506 nm的亚微米级粒子。另外，通过光谱学证明了交替电荷改性的TiO ₂纳米颗粒的逐层沉积。由于有机磷偶联剂广泛用于表面改性，特别是过渡金属氧化物，所显示的路线代表了在纳米颗粒表面上产生几乎不依赖pH的电荷的一般方法。

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Surface-Charged Zirconia Nanoparticles Prepared by Organophosphorus Surface Functionalization with Ammonium or Sulfonate Groups

Organophosphorus coupling agents bearing permanently charged functional groups (either cationic quaternary ammonium or anionic sulfonates) were synthesized and used for the modification of zirconia nanoparticles with a diameter <10 nm. Surface functionalization was confirmed by FTIR and solid-state NMR spectroscopy. Surface coverages up to 2.3–2.4 molecules/nm² were achieved for modification with these charged coupling agents. The pH-dependent charge measurements of homogeneously modified particles showed stable surface charges over a wide range of pH for both ammonium- and sulfonate-functionalized particles. Surface charge measurements of particles co-functionalized with charged coupling molecules and uncharged methyl phosphonic acid revealed a decreasing charge density with increasing amount of uncharged coupling agent. Thus, an adjustment of charges by co-functionalization was obtained on the particle surface. The thus-formed surface-charged colloids were used in a second step for electrostatic-driven aggregation phenomena necessary for layer-by-layer processes. Sulfonate-modified negatively charged SiO₂ submicrometer particles of 506 nm in diameter were decorated with ammonium-modified ZrO₂ nanoparticles. In addition, a layer-by-layer deposition of alternating charge-modified TiO₂ nanoparticles was proven by optical spectroscopy. Due to the broad applicability of organophosphorus coupling agents for surface modification, particularly for transition-metal oxides, the shown route represents a general method for the creation of almost pH-independent charges on the surface of nanoparticles.

更新日期：2019-08-08

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