In situ synthesis and stabilization of PVP-coated aluminum nanoparticles by one-step pulsed laser ablation in liquid: Investigation and quantification of PVP coverage effects

This study explored the use of one-step pulsed laser ablation (PLA) in liquid process for in situ synthesis of polyvinylpyrrolidone (PVP) coated highly-stabilized Al nanoparticles (NPs). The effect of different process variables such as laser energy, PVP concentration, and PVP chain length on the composition, size, distribution, and stability of the synthesized NPs was investigated. The results showed that adding PVP to the solution led to smaller average size of NPs with a more uniform distribution, and enhanced resistance to aggregation. This study also revealed that while PVP only partially inhibited the reaction between Al NPs and oxygen during NP generation, it could provide excellent blocking performance against hydroxylation to NPs in subsequent aging experiments. The concept of polymer coverage was introduced to quantify the protective effect of PVP polymers on Al NPs. At 0.1 J laser energy and a K-30 PVP concentration of 10 g/L, a polymer coverage value of 6773 was achieved, maximizing the amount of polymer per unit NP surface area. It was verified that Al NPs' reactivity was most efficiently suppressed under this condition. However, it was observed that the critical polymer coverage value required to suppress the reaction of Al NPs with their surroundings depended on process variables such as laser energy and polymer chain length. This study also confirmed that using high molecular weight polymers can further improve the anti-agglomeration performance and ablation efficiency while lowering the required critical polymer coverage value.