New routes to control nanomaterials' synthesis
The use of NPs with dimensions up to 100 nm is continuously increasing in biomedical drug release, electronic devices and the manufacturing industry. In most applications, specific physical properties are desired. The key to obtaining NPs with precisely tailored properties is the capability to control and fine-tune their shape and size during their synthesis. With EU funding, the project SNOW CONTROL (Integrated real-time measurement platforms for nanoparticles and nanoparticle thin films) made the first steps towards full feedback control of NP films' synthesis by integrating dedicated measuring techniques. Specifically, researchers focused on dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). The complementary SAXS and DLS techniques have been optimised to meet the requirements of ambitious time-resolved monitoring of NPs during ongoing synthesis. For this purpose, SAXS instrument performance was enhanced by the implementation of an X-ray metal jet source. The project team also developed an innovative fibre remote DLS probe for in situ measurements. The new devices were extensively tested separately on commercially available gold NPs of known size, before simultaneous DLS and SAXS measurements were performed during synthesis of silica NPs. The zeta potential (a dispersion measure) was monitored at the end of the production process because only then is the stability of the end product of interest. In addition, a second platform was developed that combines a laser-based NP fluorescence sensor with a reflection high-energy electron diffraction (RHEED) analyser. Project partners redesigned an existing liquid injection/chemical vapour deposition unit that was integrated with the RHEED analyser and the in-line ultraviolet flux monitor. The platform has already been used to grow silicon NP-based thin films successfully. SNOW CONTROL technology for in-line measurements will provide the currently missing link in the production chain for NPs and NP-based thin films. By monitoring the synthesis process in real time, feedback could be applied when needed to ensure standardised and repeatable quality that will enable their optimal performance in a wide range of applications. Watch the project’s video here.
Keywords
Nanoparticles, thin films, SNOW CONTROL, dynamic light scattering, small-angle X-ray scattering