Loading of PNIPAM Based Microgels with CoFe2O4 Nanoparticles and Their Magnetic Response in Bulk and at Surfaces
Loading of PNIPAM Based Microgels with CoFe2O4 Nanoparticles and Their Magnetic Response in Bulk and at Surfaces
复制标题
DOI：
10.1021/acs.jpcb.5b03778
复制
发表时间：
2015-09-10
影响因子：
3.3
通讯作者：
von Klitzing, Regine
中科院分区：
文献类型：
--
作者：
Backes, Sebastian;Witt, Marcus U.;von Klitzing, Regine
本文研究了磁性纳米粒子（MNP：CoFe2O4@PAA（PAA =聚丙烯酸））在温敏性聚N-异丙基丙烯酰胺（PNIPAM）微凝胶粒子上的负载及其对外磁场的响应。通过透射电子显微镜（TEM）分析MNP摄取。显然，MNP和微凝胶的电荷组合对MNP的摄取起着重要作用，但它不能解释整个摄取过程。MNP吸收导致尺寸和电泳迁移率的变化，这是通过动态光散射（DLS）和Zetasizer研究的。负载MNP的微凝胶保持了其热敏性，并显示出磁性分离性，被认为是磁性微凝胶。利用扫描力显微镜和压痕实验研究了磁性微凝胶在表面吸附后的性质。磁性微凝胶显示出沿着平行于表面的磁场的伸长，而微凝胶的高度（垂直于表面和磁场）被压缩。这一结果与磁场中铁凝胶体积变化的模拟结果吻合得很好。
The present paper addresses the loading of thermoresponsive poly-N-isopropylacrylamide (PNIPAM) based microgel particles with magnetic nanoparticles (MNP: CoFe2O4@PAA (PAA = poly(acrylic acid))) and their response to an external magnetic field. The MNP uptake is analyzed by transmission electron microscopy (TEM). Obviously, the charge combination of MNP and microgels plays an important role for the MNP uptake, but it does not explain the whole uptake process. The MNP uptake results in changes of size and electrophoretic mobility, which is investigated by dynamic light scattering (DLS) and a Zetasizer. The microgels loaded with MNP preserve their thermosensitivity, and they show magnetic separability and are considered as magnetic microgels. After adsorption at a surface the magnetic microgels are studied with a scanning force microscope and indentation experiments. The magnetic microgels show an elongation along the magnetic field parallel to the surface while the height of the microgels (perpendicular to the surface and to the magnetic field) is compressed. This result is in good agreement with simulations of volume change of ferrogels in a magnetic field.