Surface forces between bottlebrush polymer layers.

In this review, I summarize recent experimental investigations of surface and friction forces between bottlebrush structure macromolecules including biolubricants and biomimetic ones by direct force measurements. I also discuss recent experimental investigations of synergy in lubrication in which a question, 'How do lubricants act together?', is aimed to be answered. Lastly, challenges and opportunities for developing efficient lubricating systems are outlined. • Extremely low friction force in the synovial joint is achieved by biolubricants. • Biomimetic bottlebrush polymers are able to reduce friction. • Bottlebrush polymers with small molecules may reinforce lubricating ability. • Synergy in lubrication still remains to be explored. [ABSTRACT FROM AUTHOR]