Colloid and Polymer Science

, Volume 297, Issue 1, pp 1–12 | Cite as

Precision polymer network science with tetra-PEG gels—a decade history and future

  • Mitsuhiro ShibayamaEmail author
  • Xiang Li
  • Takamasa Sakai
Invited Review


Tetra-PEG gels, near-ideal polymer networks prepared by cross-end-coupling of A and B tetra-functional poly(ethylene glycol) (PEG) prepolymers having complementary end groups, were first fabricated in 2008. Comparisons of the mechanical properties with those of theoretical predictions indicate negligible fractions of defects and/or entanglements. Small-angle neutron scattering profiles of Tetra-PEG gels are very similar to those of the corresponding polymer solutions, suggesting negligible inhomogeneities originated from cross-linking. Due to the remarkable mechanical properties, extremely low structural inhomogeneities, and biocompatibility, tetra-PEG gels have gathered much attention since its discovery. The number of citation of Tetra-PEG gels is now over 2700 and is still growing rapidly. Chemical reaction kinetic studies also show a high degree of cross-linking reaction and its tunability, which leads to an idea of cross-linking probability tuned (p-tuned) networks. Versatility of the cross-coupling reactions allows us to prepare not only hydrogels but also organogels and ion gels, copolymer gels, non-stoichiometric gels, and so on. A decade history of the Tetra-PEG gels is reviewed with a variety of potential applications encompassing multiresponsive systems.

Graphical abstract


Tetra-PEG gel Polymer gels Cross-end-coupling Inhomogeneities Small-angle neutron scattering 



This work was partially supported by the Ministry of Education, Science, Sports and Culture, Japan (Grants-in-Aid for Scientific Research (A), Nos. 18205025 (2006-2008), 22245018 (2010-2012), 25248027 (2013-2015), and 16H02277 (2016-2019), and for Scientific Research on Priority Areas, No. 18068004 (2006-2010). The SANS experiments were performed with the approval of Institute for Solid State Physics, The University of Tokyo, at Japan Atomic Energy Agency, Tokai, Japan, 40m-SANS, HANARO, Korea, and QUOKKA, ANSTO, Australia. The authors acknowledge stimulating discussions with Prof. Ung-il Chung, The University of Tokyo.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no competing interest.


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© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute for Solid State PhysicsThe University of TokyoKashiwaJapan
  2. 2.Department of Bioengineering, Graduate School of EngineeringThe University of TokyoTokyoJapan

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