Optimizing Size Distribution of Carbon Spheres to Enhance Polymer Composite Performance

Carbon polymer composites are valued for their exceptional properties and diverse applications. By combining carbon nano and micro-materials with polymeric matrices, these composites exhibit enhanced structural and functional properties, making them ideal for electronics, energy storage, and biomedicine. A critical factor influencing the performance of these composites is the size distribution of the carbon particles. Proper size control determines mechanical properties, interfacial bonding, and overall performance, ensuring uniform distribution and desired thermal or electrical conductivity. We have fabricated carbon spheres (CS) via hydrothermal carbonization (HTC) of sucrose. The resultant CS have diameters ranging from hundreds of nanometers to a few micrometers. To enhance the size distribution, we varied the sucrose concentration in the precursor solution and improved cleaning and filtration methods after HTC. To separate the spheres by size, a microfluidic pinched flow fractionation device was fabricated using 3D printing. This passive sorting technique allows particles to choose their path based on size, with all CS of a given size following equivalent migration paths. The CS were characterized using SEM and AFM to assess the effectiveness of the method.