The present disclosure relates to new and optimized processes for the preparation of micro- and nano-scale capsules containing lubricant chemical additives. The present disclosure also relates to micro- and nano-scale capsules prepared by such processes, which are useful in a variety of applications, including automotive lubricants, diesel lubricants, industrial lubricants, metal-working lubricants, coolants, and process fluids. Micro- and nano-scale capsules prepared as described herein have the required properties that such capsules need to exhibit in order to function effectively and meet the requirements imposed by engine lubrication conditions. The microcapsules may be dispersed in a lubricating oil such that the lubricant exhibits improved stability and anti-wear performance, thereby improving engine fuel efficiency and performance.