Magnetic Particle Self-Assembly at Functionalized Interfaces

被引：12

作者：

Saini, Apurve ^{[1
]}

Theis-Broehl, Katharina ^{[2
]}

Koutsioubas, Alexandros ^{[3
]}

Krycka, Kathryn L. ^{[4
]}

Borchers, Julie A. ^{[4
]}

Wolff, Max ^{[1
]}

机构：

[1] Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden

[2] Univ Appl Sci, Bremerhaven, Germany

[3] Forschungszentrum Julich GmbH, Julich Ctr Neutron Sci JCNS, Heinz Maier Leibnitz Zentrum MLZ, D-85748 Garching, Germany

[4] NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA

来源：

LANGMUIR | 2021年 / 37卷 / 14期

基金：

美国国家科学基金会;

关键词：

NANOPARTICLES; REFLECTOMETER; SIZE;

D O I：

10.1021/acs.langmuir.0c03235

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

We study the assembly of magnetite nanoparticles in water-based ferrofluids in wetting layers close to silicon substrates with different functionalization without and with an out-of-plane magnetic field. For particles of nominal sizes 5, 15, and 25 nm, we extract density profiles from neutron reflectivity measurements. We show that self-assembly is only promoted by a magnetic field if a seed layer is formed at the silicon substrate. Such a layer can be formed by chemisorption of activated N-hydroxysuccinimide ester-coated nanoparticles at a (3-aminopropyl)triethoxysilane functionalized surface. Less dense packing is reported for physisorption of the same particles at a piranha-treated (strongly hydrophilic) silicon wafer, and no wetting layer is found for a self-assembled monolayer of octadecyltrichlorosilane (strongly hydrophobic) at the interface. We show that once the seed layer is formed and under an out-of-plane magnetic field further wetting layers assemble. These layers become denser with time, larger magnetic fields, higher particle concentrations, and larger moment of the nanoparticles.

引用

页码：4064 / 4071

页数：8

共 38 条

[1] Neutron time-of-flight reflectometer GRAINS with horizontal sample plane at the IBR-2 reactor: Possibilities and prospects [J].