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Structure and properties of thermoresponsive gels formed by RAFT polymerization: effect of the RAFT agent content

Polymer Journal volume 52, pages 1407–1412 (2020)Cite this article

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In the field of polymer science, polymer gels have attracted great attention, from interest in their fundamental properties to interest in their materials, functionalities, and applications. To date, researchers have developed various polymer gels with superior properties, including smart gels, self-oscillating gels, high-mechanical-strength gels, self-healing gels, and a highly ordered homogenous gel [1,2,3,4,5,6]. Among these, poly(N-isopropylacrylamide) (PNIPAAm)-based hydrogels exhibit swelling–deswelling volume transitions in response to temperature. Because the transition temperature can be controlled at approximately human body temperature, they have potential applications in biomaterials as well as various functional soft materials [7,8,9]. For these functionalities, the design of the polymer network structures plays an important role in controlling their properties, including the mechanical strength, swelling ratio, and swelling–deswelling kinetics.

Free radical polymerization (FRP) using a chemical crosslinker with two vinyl groups is one of the most common methods of obtaining polymer gels because various monomers are available. This method is widely used to prepare PNIPAAm gels; however, polymer gels prepared by FRP have inhomogeneous structures, which is attributed to slow initiation reactions, fast propagation reactions, and the fast consumption of chemical crosslinkers [10]. Thus, achieving the precise control of the resulting polymer network structure has been a significant issue, and controlled radical polymerization techniques have attracted much attention [11,12,13,14,15,16]. Miyata and coworkers have prepared PNIPAAm gels by atom transfer radical polymerization (ATRP) using a chemical crosslinker in aqueous media [12]. Recently, not only ATRP but also reversible addition-fragmentation chain transfer (RAFT) polymerization has been utilized to design polymer networks composed of poly(acrylic acid), poly(butyl acrylate), and PNIPAAm [13,14,15,16]. Liu et al. have reported that PNIPAAm gels prepared by RAFT polymerization showed faster deswelling kinetics than those prepared by FRP [15]; however, the other prosperities of the gel lack systematic study. In addition, the gelation efficiency in RAFT polymerization systems is low [16], which hinders the application of RAFT to the design of polymer gels. Thus, the systematic investigation of the structure and swelling–deswelling property of the gel prepared by RAFT polymerization is still in the rudimentary stage.

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References

  1. Niiyama E, Uto K, Lee CM, Sakura K, Ebara M. Alternating magnetic field-triggered switchable nanofiber mesh for cancer thermo-chemotherapy. Polymers. 2018;10:1018.

    Article  Google Scholar 

  2. Masuda T, Ueki T, Tamate R, Matsukawa K, Yoshida R. Chemomechanical motion of a self-oscillating gel in a protic ionic liquid. Angew Chem Int Ed. 2018;57:16693–7.

    Article  CAS  Google Scholar 

  3. Sakai T, Matsunaga T, Yamamoto Y, Ito C, Yoshida R, Suzuki S, et al. Design and fabrication of a high-strength hydrogel with ideally homogeneous network structure from tetrahedron-like macromonomers. Macromolecules. 2008;41:5379–84.

    Article  CAS  Google Scholar 

  4. Chen Y, Tan Z, Wang W, Peng Y, Narain R. Injectable, self-healing, and multi-responsive hydrogels via dynamic covalent bond formation between benzoxaborole and hydroxyl groups. Biomacromolecules. 2019;20:1028–35.

    Article  CAS  Google Scholar 

  5. Tamate R, Hashimoto K, Horii T, Hirasawa M, Li X, Shibayama M, et al. Self-healing micellar ion gels based on multiple hydrogen bonding. Adv Mater. 2018;30:1802792.

    Article  Google Scholar 

  6. Li X, Nakagawa S, Tsuji Y, Watanabe N, Shibayama M. Polymer gel with a flexible and highly ordered three-dimentional network synthesized via bond parcolation. Sci Adv. 2019;5:eaax8647.

    Article  CAS  Google Scholar 

  7. Masuda T, Tsuji T, Koizumi H, Takai M. Strong cationic radical initiator-based design of a thermoresponsive hydrogel showing drastic volume transition. Macromol Chem Phys. 2020;221:1900507.

    Article  CAS  Google Scholar 

  8. Zheng WJ, An N, Yang JH, Zhou J, Chen YM. Tough Al-alginate/Poly(N-isopropylacrylamide) hydrogel with tunable LCST for soft robotics. ACS Appl Mater Interfaces. 2015;7:1758–64.

    Article  CAS  Google Scholar 

  9. Matsukawa K, Masuda T, Akimoto AM, Yoshida R. A surface-grafted thermoresponsive hydrogel in which the surface structure dominates the bulk properties. Chem Commun. 2016;52:11064–7.

    Article  CAS  Google Scholar 

  10. Dusek K, Duskova-Smrckova M. Network structure formation during crosslinking of organic coating systems. Prog Polym Sci. 2000;25:1215–60.

    Article  CAS  Google Scholar 

  11. Yoon JA, Gayathri C, Gil RR, Kowalewski T, Matyjaszewski K. Comparison of thermoresponsive deswelling kinetics of poly(2-(2-mthoxyethoxy)ethyl methacrylate hydrogels prepared by ATRP and FRP. Macronolecules. 2010;43:4791–7.

    Article  CAS  Google Scholar 

  12. Norioka C, Kawamura A, Miyata T. Mechanical and responsive properties of temperature-responsive gels prepared via atom transfer radical polymerization. Polym Chem. 2017;8:6050–7.

    Article  CAS  Google Scholar 

  13. Cavalli F, Pfeifer C, Arens L, Barner L, Wilhelm M. Analysis of the local mobility of RAFT mediated poly(acrylic acid) networks via low field 1H-NMR techniques for investigation of the network topology. Macromol Chem Phys. 2020;221:1900387.

    Article  CAS  Google Scholar 

  14. Henkel R, Vana P. The Influence of RAFT on the Microstructure and Mechanical Properties of Photopolymerized Poly(butyl acrylate) Networks. Macromol Chem Phys. 2014;215:182–9.

    Article  CAS  Google Scholar 

  15. Liu Q, Zhang P, Qing A, Lan Y, Lu M. Poly(N-isopropylacrylamide) hydrogels with improved shrinking kinetics by RAFT polymerization. Polymer. 2006;47:2330–6.

    Article  CAS  Google Scholar 

  16. Ida S, Furukawa S, Tanimoto S, Hirokawa Y. Growing crosslinker: gel synthesis using novel divinyl crosslinker with expanding chain-length between vinyl groups by RAFT polymerization. Koubunshi Ronbunshu. 2015;72:440–6.

    Article  CAS  Google Scholar 

  17. Sakota K, Tabata D, Sekiya H. Macronolecular crowding modifies the impact of specific hofmeister ions on the coil-globule transition of PNIPAM. J Phys Chem B. 2015;119:10334–40.

    Article  CAS  Google Scholar 

  18. Hirotsu S. Softening of bulk modulus and negative Poisson’s ratio near the volume phase transition of polymer gels. J Chem Phys. 1991;94:3949–57.

    Article  CAS  Google Scholar 

  19. Shibayama M, Nagai K. Shrinking kinetics of poly(N-isopropylacrylamide) gels T-jumped across their volume phase transition temperatures. Macromolecules. 1999;32:7461–8.

    Article  CAS  Google Scholar 

  20. Yoshida R, Uchida K, Kaneko Y, Sakai K, Kikuchi A, Sakurai Y, et al. Comb-type grafted hydrogels with rapid de-swelling response to temperature changes. Nature. 1995;374:240–2.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan to TM. We are grateful to Prof. Ryo Yoshida, Prof. Aya M. Akimoto, and Dr. Takafumi Enomoto (The University of Tokyo) for the use of the GPC system.

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  1. Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan

    Tsukuru Masuda & Madoka Takai

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Correspondence to Tsukuru Masuda or Madoka Takai.

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Masuda, T., Takai, M. Structure and properties of thermoresponsive gels formed by RAFT polymerization: effect of the RAFT agent content. Polym J 52, 1407–1412 (2020). https://doi.org/10.1038/s41428-020-00401-x

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