Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Original Article
  • Published:

pH-responsive aggregation control of multiarm star polymers depending on the ionic segment sequence of arm polymers

Polymer Journal volume 54, pages 715–725 (2022)Cite this article

Subjects

Abstract

A deep understanding of the effect of the ionic density in a polymer on the solution properties would contribute to the development of novel stimuli-responsive materials. To this end, a multibranched and highly dense structure is an attractive platform for the accumulation of ionizable groups. In this study, we focus on core-crosslinked multiarm star polymers having ionizable poly(acrylic acid) (PAA) segments in the arms with different sequences to evaluate the density effect of ionic segments on pH-responsive properties. Two types of star polymers with a PAA block on the outer or inner side of an arm chain in combination with a hydrophilic poly(2-hydroxyethyl acrylate) (PHEA) block were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. These star polymers exhibited aggregation behavior different from the corresponding linear block polymer in an acidic aqueous solution. Dynamic light scattering analysis in water revealed that the star polymer with PAA in the outer layer formed larger aggregates than the star polymer with the inverse layer structure, and the pH-responsive change of the hydrodynamic radius in water depends on the sequence in the arm polymers. This behavior resulted from the balance of hydrogen bonding between PAA and PHEA segments and PAA electrostatic repulsion.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1
Scheme 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

Similar content being viewed by others

References

  1. Dai S, Ravi P, Tam KC. Thermo- and photo-responsive polymeric systems. Soft Matter. 2009;5:2513–33.

    Article  CAS  Google Scholar 

  2. Roy D, Cambre JN, Sumerlin BS. Future perspectives and recent advances in stimuli-responsive materials. Prog Polym Sci. 2010;35:278–301.

    Article  CAS  Google Scholar 

  3. Kocak G, Tuncer C, Bütün V. pH-Responsive polymers. Polym Chem. 2017;8:144–76.

    Article  CAS  Google Scholar 

  4. Mane SR, Sathyan A, Shunmugam R. Biomedical applications of pH-responsive amphiphilic polymer nanoassemblies. ACS Appl Nano Mater. 2020;3:2104–17.

    Article  CAS  Google Scholar 

  5. Li M-H, Keller P. Stimuli-responsive polymer vesicles. Soft Matter. 2009;5:927–37.

    Article  CAS  Google Scholar 

  6. Alarcón CDH, Pennadam S, Alexander C. Stimuli responsive polymers for biomedical applications. Chem Soc Rev. 2005;34:276–85.

    Article  Google Scholar 

  7. Schmaljohann D. Thermo- and pH-responsive polymers in drug delivery. Adv Drug Deliv Rev. 2006;58:1655–70.

    Article  CAS  PubMed  Google Scholar 

  8. Stuart MAC, Huck WTS, Genzer J, Müller M, Ober C, Stamm M, et al. Emerging applications of stimuli-responsive polymer materials. Nat Mater. 2010;9:101–13.

    Article  PubMed  Google Scholar 

  9. Bütün V, Armes SP, Billingham NC. Synthesis and aqueous solution properties of near-monodisperse tertiary amine methacrylate homopolymers and diblock copolymers. Polymer. 2001;42:5993–6008.

    Article  Google Scholar 

  10. Narumi A, Fuchise K, Kakuchi R, Toda A, Satoh T, Kawaguchi S, et al. A versatile method for adjusting thermoresponsivity: synthesis and ‘Click’ reaction of an azido end-functionalized poly(N-isopropylacrylamide). Macromol Rapid Commun. 2008;29:1126–33.

    Article  CAS  Google Scholar 

  11. Luo C, Liu Y, Li Z. Thermo- and pH-responsive polymer derived from methacrylamide and aspartic acid. Macromolecules. 2010;43:8101–8.

    Article  CAS  Google Scholar 

  12. Lim J, Matsuoka H, Yusa S-I, Saruwatari Y. Temperature-responsive behavior of double hydrophilic carboxy-sulfobetaine block copolymers and their self-assemblies in water. Langmuir. 2019;35:1571–82.

    Article  CAS  PubMed  Google Scholar 

  13. Ida S, Nishisako D, Fujiseki A, Kanaoka S. Thermoresponsive properties of polymer hydrogels induced by copolymerization of hydrophilic and hydrophobic monomers: comprehensive study of monomer sequence and water affinity. Soft Matter. 2021;17:6063–72.

    Article  CAS  PubMed  Google Scholar 

  14. Kuckling D, Wycisk A. Stimuli‐responsive star polymers. J Polym Sci Part A: Polym Chem. 2013;51:2980–94.

    Article  CAS  Google Scholar 

  15. Voit BI, Lederer A. Hyperbranched and highly branched polymer architectures—synthetic strategies and major characterization aspects. Chem Rev. 2009;109:5924–73.

    Article  CAS  PubMed  Google Scholar 

  16. Lee CC, MacKay JA, Fréchet JMJ, Szoka FC. Designing dendrimers for biological applications. Nat Biotechnol. 2005;23:1517–26.

    Article  CAS  PubMed  Google Scholar 

  17. Inoue K. Functional dendrimers, hyperbranched and star polymers. Prog Polym Sci. 2000;25:453–571.

    Article  CAS  Google Scholar 

  18. Ren JM, McKenzie TG, Fu Q, Wong EHH, Xu J, An Z, et al. Star polymers. Chem Rev. 2016;116:6743–836.

    Article  CAS  PubMed  Google Scholar 

  19. Blencowe A, Tan JF, Goh TK, Qiao GG. Core cross-linked star polymers via controlled radical polymerisation. Polymer. 2009;50:5–32.

    Article  CAS  Google Scholar 

  20. Gao H, Matyjaszewski K. Synthesis of functional polymers with controlled architecture by CRP of monomers in the presence of cross-linkers: from stars to gels. Prog Polym Sci. 2009;34:317–50.

    Article  CAS  Google Scholar 

  21. Ida S, Toyama Y, Takeshima S, Kanaoka S. Thermoresponsive core cross-linked star-shaped poly(N-isopropylacrylamide) for reversible and controlled aggregation of nanoscale molecular units. Polym J. 2020;52:359–63.

    Article  CAS  Google Scholar 

  22. Sharker KK, Takeshima S, Toyama Y, Ida S, Kanaoka S, Yusa S-I. pH- and thermo-responsive behavior of PNIPAM star containing terminal carboxy groups in aqueous solutions. Polymer. 2020;203:122735.

    Article  CAS  Google Scholar 

  23. Connal LA, Li Q, Quinn JF, Tjipto E, Caruso F, Qiao GG. pH-responsive poly(acrylic acid) core cross-linked star polymers: morphology transitions in solution and multilayer thin films. Macromolecules. 2008;41:2620–6.

    Article  CAS  Google Scholar 

  24. Qu C, Shi Y, Jing B, Gao H, Zhu Y. Probing the inhomogeneous charge distribution on annealed polyelectrolyte star polymers in dilute aqueous solutions. ACS Macro Lett. 2016;5:402–6.

    Article  Google Scholar 

  25. Luo S, Xu J, Zhu Z, Wu C, Liu S. Phase transition behavior of unimolecular micelles with thermoresponsive poly(N-isopropylacrylamide) coronas. J Phys Chem B. 2006;110:9132–9.

    Article  CAS  PubMed  Google Scholar 

  26. Xu J, Luo S, Shi W, Liu S. Two-stage collapse of unimolecular micelles with double thermoresponsive coronas. Langmuir. 2006;22:989–97.

    Article  CAS  PubMed  Google Scholar 

  27. Plamper FA, Ruppel M, Schmalz A, Borisov O, Ballauff M, Müller AHE. Tuning the thermoresponsive properties of weak polyelectrolytes: aqueous solutions of star-shaped and linear poly(N,N-dimethylaminoethyl methacrylate). Macromolecules. 2007;40:8361–6.

    Article  CAS  Google Scholar 

  28. Chen Q, Cao X, Liu H, Zhou W, Qin L, An Z. pH-responsive high internal phase emulsions stabilized by core cross-linked star (CCS) polymers. Polym Chem. 2013;4:4092–102.

    Article  CAS  Google Scholar 

  29. Hou L, Chen Q, An Z, Wu P. Understanding the thermosensitivity of POEGA-based star polymers: LCST-type transition in water vs. UCST-type transition in ethanol. Soft Matter. 2016;12:2473–80.

    Article  CAS  PubMed  Google Scholar 

  30. Lang X, Lenart WR, Sun JEP, Hammouda B, Hore MJA. Interaction and conformation of aqueous poly(N-isopropylacrylamide) (PNIPAM) star polymers below the LCST. Macromolecules. 2017;50:2145–54.

    Article  CAS  Google Scholar 

  31. Bywater S. Preparation and properties of star-branched polymers. Adv Polym Sci. 1979;30:89–116.

    Article  CAS  Google Scholar 

  32. Kanaoka S, Sawamoto M, Higashimura T. Star-shaped polymers by living cationic polymerization. 1. Synthesis of star-shaped polymers of alkyl and vinyl ethers. Macromolecules. 1991;24:2309–13.

    Article  CAS  Google Scholar 

  33. Baek K-Y, Kamigaito M, Sawamoto M. Star-shaped polymers by metal-catalyzed living radical polymerization. 1. Design of Ru(II)-based systems and divinyl linking agents. Macromolecules. 2001;34:215–21.

    Article  CAS  Google Scholar 

  34. Barner-Kowollik C, Davis TP, Stenzel MH. Synthesis of star polymers using RAFT polymerization: what is possible? Aust J Chem. 2006;59:719–27.

    Article  CAS  Google Scholar 

  35. Moad G, Rizzardo E, Thang SH. Living radical polymerization by the RAFT process. Aust J Chem. 2005;58:379–410.

    Article  CAS  Google Scholar 

  36. Moad G, Rizzardo E, Thang SH. Living radical polymerization by the RAFT process—a second update. Aust J Chem. 2009;62:1402–72.

    Article  CAS  Google Scholar 

  37. Gregory A, Stenzel MH. Complex polymer architectures via RAFT polymerization: From fundamental process to extending the scope using click chemistry and nature’s building blocks. Prog Polym Sci. 2012;37:38–105.

    Article  CAS  Google Scholar 

  38. Swift T, Swanson L, Geoghegan M, Rimmer S. The pH-responsive behaviour of poly(acrylic acid) in aqueous solution is dependent on molar mass. Soft Matter. 2016;12:2542–9.

    Article  CAS  PubMed  Google Scholar 

  39. Loiseau J, Doërr N, Suau JM, Egraz JB, Llauro MF, Ladavière C, et al. Synthesis and characterization of poly(acrylic acid) produced by RAFT polymerization. Application as a very efficient dispersant of CaCO3, Kaolin, and TiO2. Macromolecules. 2003;36:3066–77.

    Article  CAS  Google Scholar 

  40. André X, Zhang M, Müller AHE. Thermo- and pH-responsive micelles of poly(acrylic acid)-block-poly(N,N-diethylacrylamide). Macromol Rapid Commun. 2005;26:558–63.

    Article  Google Scholar 

Download references

Acknowledgements

The authors thank Prof. Dr. Takaya Terashima (Kyoto University) for performing SEC-MALS measurements and Ms. Yoko Mizoue (University of Hyogo) for assistance with DLS measurements.

Author information

Authors and Affiliations

  1. Department of Materials Science, Faculty of Engineering, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga, 522-8533, Japan

    Hiroomi Kitajima, Shohei Ida & Shokyoku Kanaoka

  2. Department of Applied Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan

    Shukanta Bhowmik & Shin-ichi Yusa

Authors
  1. Hiroomi Kitajima
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Shohei Ida
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Shukanta Bhowmik
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Shin-ichi Yusa
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Shokyoku Kanaoka
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Shokyoku Kanaoka.

Ethics declarations

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kitajima, H., Ida, S., Bhowmik, S. et al. pH-responsive aggregation control of multiarm star polymers depending on the ionic segment sequence of arm polymers. Polym J 54, 715–725 (2022). https://doi.org/10.1038/s41428-022-00621-3

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41428-022-00621-3

Search

Advanced search

Quick links