Virtanen Otto L J, Purohit Ashvini, Brugnoni Monia, Wöll Dominik, Richtering Walter
Institute of Physical Chemistry, RWTH Aachen University.
Institute of Physical Chemistry, RWTH Aachen University;
J Vis Exp. 2016 Sep 8(115):54419. doi: 10.3791/54419.
Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this work, we use single particle tracking of fluorescently labeled PNIPAM microgels as a showcase for tuning microgel size by a rapid non-stirred precipitation polymerization procedure. This approach is well suited for prototyping new reaction compositions and conditions or for applications that do not require large amounts of product. Microgel synthesis, particle size and structure determination by dynamic and static light scattering are detailed in the protocol. It is shown that the addition of functional comonomers can have a large influence on the particle nucleation and structure. Single particle tracking by wide-field fluorescence microscopy allows for an investigation of the diffusion of labeled tracer microgels in a concentrated matrix of non-labeled microgels, a system not easily investigated by other methods such as dynamic light scattering.
刺激敏感型聚（N-异丙基丙烯酰胺）（PNIPAM）微凝胶在基础研究中有各种潜在的实际应用。在本工作中，我们将荧光标记的PNIPAM微凝胶的单粒子追踪作为一个范例，用于通过快速非搅拌沉淀聚合法调节微凝胶尺寸。这种方法非常适合新反应组成和条件的原型设计，或适用于不需要大量产物的应用。该方案详细介绍了通过动态和静态光散射进行微凝胶合成、粒径和结构测定。结果表明，功能性共聚单体的添加对粒子成核和结构有很大影响。通过宽场荧光显微镜进行的单粒子追踪可以研究标记示踪微凝胶在未标记微凝胶的浓缩基质中的扩散，而这种系统用动态光散射等其他方法不易研究。
