APDMS mediated self-assembly of alumina nanospheres

We report a simple method to create spherical aggregates of alumina nanospheres. Alumina nanospheres were dispersed in ethanol and capped by 3-Aminopropyldimethylethoxysilane (APDMS). APDMS acts as a cross linker between nanoparticles to form micro/nano spherical aggregates. Created spheres were distributed on Si and SiN substrates utilizing spin-coating method. Eventually, spherical aggregates with diameter distribution of 400-2800 nm were achieved. The spatial distribution and size of the spherical structures were adjustable by changing the concentration of the used surfactant, APDMS. Higher concentration of surfactant resulted in more aggregation of alumina nanoparticles leading to larger spheres in diameter. Field-Emission Scanning Electron Microscope (FE-SEM) was used to characterize and quantize micro/nanostructures distribution and shape.