Concentrated Polymer Brush as Reciprocating Seal Material for Low Leakage and Low Friction

Chiharu Tadokoro, Kosuke Sato, Takuo Nagamine, Ken Nakano, Shinya Sasaki, Takaya Sato, Keita Sakakibara, Yoshinobu Tsujii

Research output: Contribution to journalArticle


Recently, concentrated polymer brushes (CPBs) have attracted much attention as potential tribomaterials showing an ultralow friction coefficient (e.g., 10−4 in a microtribological analysis). In this study, a homemade apparatus modeling reciprocating seals was developed, which consisted of an inner steel rod and an outer steel ring with a narrow clearance less than several tens of micrometers. A few-micrometer-thick CPB film of poly(methyl methacrylate) well-swollen with an ionic liquid was prepared on each steel surface, and the impact of applying the CPB film to the clearance of reciprocating seals was examined by measuring the leakage rate of a fluid and the friction coefficient in reciprocating motion. The results showed that the CPB film narrowed the clearance between the two steel surfaces, which improved its sealing performance. In addition, the CPB film yielded a quite low friction coefficient (e.g., 10−3), which assured its smooth motion with small energy loss.

Original languageEnglish
Pages (from-to)20-27
Number of pages8
JournalTribology Transactions
Issue number1
Publication statusPublished - 2 Jan 2020



  • Sealing technology
  • concentrated polymer brushes
  • friction-reducing coating
  • reciprocating seals

Cite this

Tadokoro, C., Sato, K., Nagamine, T., Nakano, K., Sasaki, S., Sato, T., Sakakibara, K., & Tsujii, Y. (2020). Concentrated Polymer Brush as Reciprocating Seal Material for Low Leakage and Low Friction. Tribology Transactions, 63(1), 20-27.