Hetero-aggregation of oppositely charged nanoparticles
Hetero-aggregation of oppositely charged nanoparticles
复制标题
DOI：
10.1016/j.jcis.2016.12.059
复制
发表时间：
2017-04-15
影响因子：
9.9
通讯作者：
Basavaraj, Madivala G.
中科院分区：
文献类型：
--
作者：
Bansal, Pooja;Deshpande, Abhijit P.;Basavaraj, Madivala G.
异聚集是指不相同的粒子的聚集，即具有不同物理化学性质的粒子。这种现象的研究具有重要意义，因为它可以形成迷人的结构，并在许多领域得到应用，包括多孔材料和颗粒稳定乳液的合成。我们报告了一项实验研究的异聚集行为的相反的带电纳米颗粒的大小相似。本研究采用目视观察、zeta电位测量、动态光散射、扫描电子显微镜和流变学测量相结合的方法研究了异聚集现象。我们报告了聚集体尺寸、结构、流动特性的细节，通过仔细检查在混合相反带电粒子时形成的不同相来提供对异聚集的理解。实验在不同的混合分数（定义为分散体中正粒子的质量除以分散体中粒子的总质量）下进行，混合分数从0到1不等，粒子的总浓度从0.05到30 wt% （0.023-13.82 vol%）不等。在低总颗粒浓度下，观察到四种不同的混合物状态，包括带有浑浊上清的沉积物、带有清澈上清的沉积物、没有沉积物的浑浊样品和清晰的分散体。然而，在类似于7.5 wt% （3.45 vol%）以上的较高浓度下，相反带电粒子的混合物形成-低混合分数（从0.1到0.3）具有浑浊上清的颗粒凝胶，中等混合分数（从0.3到0.7）的固体状凝胶和高混合分数（从0.7到1.0）的浑浊样品。(C) 2016 Elsevier Inc.版权所有。
Hetero-aggregation refers to aggregation of particles that are not identical i.e. particles of different physical-chemical properties. The investigation of this phenomenon is important because of the fascinating structures that can be formed and their application in several fields including the synthesis of porous materials and particle stabilized emulsions. We report an experimental study of hetero-aggregation behaviour of oppositely charged nanoparticles of similar size. In this study, the hetero-aggregation phenomenon is investigated using a combination of visual observation, zeta potential measurements, dynamic light scattering, scanning electron microscopy and rheology measurements. We report details of aggregate size, structure, flow properties to provide understanding of hetero-aggregation by a careful examination of different phases formed upon mixing oppositely charged particles. The experiments were carried out at different mixingfraction (defined as the mass of positive particle in the dispersion divided by total mass of particles in the dispersion) varying from 0 to 1 with total concentration of particles ranging from 0.05 to 30 wt% (0.023-13.82 vol%). At low total particle concentration, four different states of the mixture were observed which includes sediment with turbid supernatant, sediment with clear supernatant, turbid sample with no sediment and a clear dispersion. However, at higher concentration above similar to 7.5 wt% (3.45 vol%), the mixture of oppositely charged particles form - a particulate gel with turbid supernatant at low mixing fraction (from 0.1 to 0.3), a solid-like gel at intermediate mixing fraction (from 0.3 to 0.7) and a turbid sample at high mixing fractions from 0.7 to 1.0. (C) 2016 Elsevier Inc. All rights reserved.