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Nanoparticle Gradient Materials by Centrifugation
摘要： Nanoparticle gradient materials are a unique class of functional materials. They combine the specific properties of nanoparticles with macroscopic materials. A continuous spatial gradient of the nanoparticle concentration leads to diverse physical property profiles. Therefore, these materials have a remarkable potential for applications in optics, electronics, and sensors. A novel approach for the defined and controlled synthesis of this material class is the fabrication in ultracentrifugal fields. The formation of a nanoparticle gradient by sedimentation in a gelatin solution is monitored online with optical systems inside an analytical ultracentrifuge. As soon as the desired nanoparticle concentration gradient is generated, the material is solidified by gelation and the desired gradient is fixed in the material. Application of the established theory of analytical ultracentrifugation allows simulations of the sedimentation process of the nanoparticles in advance. Thus, desired nanoparticle gradient materials can also be tailor-made and fabricated on a preparative scale. This is demonstrated for the example of spherical gold nanoparticles of different sizes, gold nanorods, mixtures thereof, and spherical superparamagnetic iron oxide nanoparticles.
关键词： composites,gradient materials,analytical ultracentrifugation,nanoparticles,polymers
更新于2025-09-23 15:21:01
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Determination of the two-dimensional distributions of gold nanorods by multiwavelength analytical ultracentrifugation
摘要： Properties of nanoparticles are influenced by various parameters like size, shape or composition. Comprehensive high throughput characterization techniques are urgently needed to improve synthesis, scale up to production and make way for new applications of multi-dimensional particulate systems. In this study, we present a method for measuring two-dimensional size distributions of plasmonic nanorods in a single experiment. Analytical ultracentrifuge equipped with a multiwavelength extinction detector is used to record the optical and sedimentation properties of gold nanorods simultaneously. A combination of sedimentation and extinction properties, both depending on diameter and length of the dispersed nanorods, is used to measure two-dimensional distributions of gold nanorod samples. The length, diameter, aspect ratio, volume, surface and cross-sectional distributions can be readily obtained from these results. As the technique can be extended to other non-spherical plasmonic particles and can be used for determining relative amounts of particles of different shapes it provides complete and quantitative insights into particulate systems.
关键词： gold nanorods,nanoparticles,multiwavelength extinction detector,two-dimensional size distributions,analytical ultracentrifugation
更新于2025-09-23 15:21:01