Colloid and Polymer Science

, Volume 297, Issue 11–12, pp 1445–1454 | Cite as

Molecular brushes with poly-2-ethyl-2-oxazoline side chains and aromatic polyester backbone manifesting double stimuli responsiveness

  • Alexander Filippov
  • Elena TarabukinaEmail author
  • Alisa Kudryavtseva
  • Emil Fatullaev
  • Mikhail Kurlykin
  • Andrey Tenkovtsev
Original Contribution


Behavior of grafted copolymers composed of aromatic polyester (PAPE) backbone and poly-2-ethyl-2-oxazoline (PEOZ) side chains differing in grafting density in aqueous solutions was studied when heated at various concentrations and pH using static and dynamic light scattering and turbidimetry. Aggregates and individual macromolecules were registered in solutions at all times. It was shown that the aggregates of the brush with higher PEOZ side chains’ grafting density undergo compaction on heating below phase separation, whereas the size of the loose polymer brush aggregates continuously increases with the increase of temperature. Phase separation temperatures of both copolymers decreased with dilution. Strong influence of pH on the thermosensitivity of both samples was shown, the copolymer solubility being decreased with the acidity decrease. The nature of the pH effect is under discussion.

Graphical abstract


Poly-2-ethyl-2-oxazoline Grafted polymers Thermoresponsive polymer brushes pH sensitivity Static light scattering Dynamic light scattering 


Funding information

The study was carried out with the financial support of the Russian Foundation for Basic Research in the framework of Research Project No. 18-03-00356_a.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

396_2019_4558_Fig12_ESM.png (15 kb)
Fig. SI1

Dependence of Ss/Sf on pH for PAPE-g-PEOZ solutions at c = 0.0015 g/cm3. (PNG 14 kb)

396_2019_4558_MOESM1_ESM.eps (39 kb)
High resolution image (EPS 39 kb)
396_2019_4558_Fig13_ESM.png (13 kb)
Fig. SI2

The values of RslowT/Rsmin at different c for sample 2. (PNG 12 kb)

396_2019_4558_MOESM2_ESM.eps (46 kb)
High resolution image (EPS 46 kb)


  1. 1.
    Terao K, Takeo Y, Tazaki M, Nakamura Y, Norisuye T (1999) Polymacromonomer consisting of polystyrene. Light scattering characterization in cyclohexane. Polym J 31:193–198Google Scholar
  2. 2.
    Zhang M, Müller AHE (2005) Cylindrical polymer brushes. J Polym Sci Part A: Polym Chem 43:3461–3481Google Scholar
  3. 3.
    Hsu H-P, Paul W, Binder K (2007) One- and two-component bottle-brush polymers: simulations compared to theoretical predictions. Macromol theory and simulations 16(7):660–689Google Scholar
  4. 4.
    Sheiko SS, Sumerlin BS, Matyjaszewski M (2008) Cylindrical molecular brushes: synthesis, characterization, and properties. Prog Polym Sci 33:759–785Google Scholar
  5. 5.
    Verduzco R, Li X, Pesek SL, Stein GE (2015) Structure, function, self-assembly, and applications of bottlebrush copolymers. Chem Soc Rev 44:2405–2420PubMedGoogle Scholar
  6. 6.
    Dutta S, Wade MA, Walsh DJ, Guironnet D, Rogers SA, Sing CE (2019) Dilute solution structure of bottlebrush polymers. Soft Matter 15:2928–2941PubMedGoogle Scholar
  7. 7.
    Filippov AP, Krasova AS, Tarabukina EB, Kashina AV, Meleshko TK, Yakimansky AV (2016) The effect of side chain length on hydrodynamic and conformational characteristics of polyimide-graft-polymethylmethacrylate copolymers in thermodynamically good solutions. J Polym Res 23:219Google Scholar
  8. 8.
    Krishnamoorthy M, Li D, Sharili AS, Gulin-Sarfraz T, Rosenholm JM, Gautrot JE (2017) Solution conformation of polymer brushes determines their interactions with DNA and transfection efficiency. Biomacromolecules 18(12):4121–4132PubMedGoogle Scholar
  9. 9.
    Weber C, Rogers S, Vollrath A, Hoeppener S, Rudolph T, Fritz N, Hoogenboom R, Schubert US (2013) Aqueous solution behavior of comb-shaped poly(2-ethyl-2-oxazoline). J Polym Sci Part A: Polymer Chemistry 51:139–148Google Scholar
  10. 10.
    Yang YQ, Guo XD, Lin WJ, Zhang LJ, Zhang CY, Qian Y (2012) Amphiphilic copolymer brush with random pH-sensitive/hydrophobic structure: synthesis and self-assembled micelles for sustained drug delivery. Soft Matter 8(2):454–464Google Scholar
  11. 11.
    Borisov OV, Zhulina EB (2005) Amphiphilic graft copolymer in a selective solvent: intramolecular structures and conformational transitions. Macromolecules 38(6):2506–2514Google Scholar
  12. 12.
    Pautov VD, Nekrasova TN, Anan’eva TD, Meleshko TK, Ilgach DM, Yakimansky AV (2013) Intramolecular mobility of side chains of poly (methacrylic acid) in regularly grafted copolyimides in solution. Polym Sci Ser A 55:526–534Google Scholar
  13. 13.
    Krasova A, Belyaeva E, Tarabukina E, Filippov A, Meleshko T, Ilgach D, Bogorad N, Yakimansky A (2012) Synthesis and solution properties of loose polymer brushes having polyimide backbone and methylmethacrylate side chains. Macromol Symp 316:32–42Google Scholar
  14. 14.
    Espinosa-Marzal RM, Nalam PC, Bolisetty S, Spencer ND (2013) Impact of solvation on equilibrium conformation of polymer brushes in solvent mixtures. Soft Matter 9:4045–4057Google Scholar
  15. 15.
    Chen G, Hoffman AS (1995) Graft copolymers that exhibit temperature induced phase transitions over a wide range of pH. Nature 373:49–52PubMedGoogle Scholar
  16. 16.
    Schlaad H, Diehl C, Gress A, Meyer M, Demirel AL, Nur Y, Bertin A (2010) Poly(2-oxazoline) s as smart bioinspired polymers. Macromol Rapid Commun 31:511–525PubMedGoogle Scholar
  17. 17.
    Roy D, Brooks WLA, Sumerlin BS (2013) New directions in thermoresponsive polymers. Chem Soc Rev 42:7214–7243PubMedGoogle Scholar
  18. 18.
    Hoogenboom R, Schlaad H (2017) Thermoresponsive poly(2-oxazoline)s, polypeptoids, and polypeptides. Polym Chem 8:24–40Google Scholar
  19. 19.
    Grube M, Leiske M, Shubert U, Nischang I (2018) POx as an alternative to PEG? A hydrodynamic and light scattering study. Macromolecules 51:1905–1916Google Scholar
  20. 20.
    Zheng A, Xue Y, Wei D, Guan Y, Xiao H (2013) Amphiphilic star block copolymers as gene carrier part I: synthesis via ATRP using calix[4]resorcinarene-based initiators and characterization. Materials Sci and Engineering 33:519–526Google Scholar
  21. 21.
    Ulrich KE, Cannizzaro CM, Langer RS, Shakesheff KM (1999) Polymeric systems for controlled drug release. Chem Rev 99:3181–3198Google Scholar
  22. 22.
    Fael H, Rafols C, Demirel AL (2018) Poly(2-ethyl-2-oxazoline) as an alternative to poly (vinylpyrrolidone) in solid dispersions for solubility and dissolution rate enhancement of drugs. J Pharm Sci 107(9):2428–2438PubMedGoogle Scholar
  23. 23.
    Mees MA, Effenberg C, Appelhans D, Hoogenboom R (2016) Sweet polymers: poly(2-1 ethyl-2-oxazoline) 2 glycopolymers by reductive amination. Biomacromolecules 17(12):4027–4036PubMedGoogle Scholar
  24. 24.
    Goddard P, Hutchinson LE, Brown J, Brookman LJ (1989) Soluble polymeric carriers for drug delivery. Part 2. Preparation and in vivo behaviour of N-acylethylenimine copolymers. J Control Release 10:5–16Google Scholar
  25. 25.
    Chen FP, Ames AE, Taylor LD (1990) Aqueous solutions of poly (ethyloxazoline) and its lower consolute phase transition. Macromolecules 23(21):4688–4695Google Scholar
  26. 26.
    Park J-S, Kataoka K (2006) Precise control of lower critical solution temperature of thermosensitive poly(2-isopropyl-2-oxazoline) via gradient copolymerization with 2-ethyl-2-oxazoline as a hydrophilic comonomer. Macromolecules 39:6622–6630Google Scholar
  27. 27.
    Strandman S, Zarembo A, Darinskii AA, Laurinmaki P, Bucher SJ, Vuorimaa E, Lemmetinen H, Tenhu H (2008) Effect of the number of arms on the association of amphiphilic star block copolymers. Macromolecules 41:8855–8864Google Scholar
  28. 28.
    Sheng Y-J, Nung CH, Tsao HK (2006) Morphologies of star-block copolymers in dilute solutions. J Phys Chem B 110:21643–21650PubMedGoogle Scholar
  29. 29.
    Amirova AI, Dudkina MM, Tenkovtsev AV, Filippov AP (2014) Self-assembly of star-shaped poly(2-isopropyl-2-oxazoline) in aqueous solutions. Colloid Polym Sci 293:239–248Google Scholar
  30. 30.
    Rueda J, Zschoche S, Komber H, Schmaljohann D, Voit B (2005) Synthesis and characterization of thermoresponsive graft copolymers of NIPAAm and 2-alkyl-2-oxazolines by the “grafting from” method. Macromolecules 38:7330–7336Google Scholar
  31. 31.
    Weber C, Wagner M, Baykal D, Hoeppener S, Paulus RM, Festag G, Altuntas E, Schacher FH, Schubert US (2013) Easy access to amphiphilic heterografted poly(2-oxazoline) comb copolymers. Macromolecules 46:5107–5116Google Scholar
  32. 32.
    Zhang N, Luxenhofer R, Jordan R (2012) Thermoresponsive poly(2-oxazoline) molecular brushes by living ionic polymerization: kinetic investigations of pendant chain grafting and cloud point modulation by backbone and side chain length variation. Macromol Chem Phys 213:973–981Google Scholar
  33. 33.
    Buhler J, Muth S, Fischer K, Schmidt M (2013) Collapse of cylindrical brushes with 2-isopropyloxazoline side chains close to the phase boundary. Macromol Rapid Commun 34:588–594PubMedGoogle Scholar
  34. 34.
    Alvaradejo GG, Nguyen HV-T, Harvey P, Gallagher NM, Le D, Ottaviani MF, Jasanoff A, Delaittre G, Johnson JA (2019) Polyoxazoline-based bottlebrush and brush-arm star polymers via ROMP: syntheses and applications as organic radical contrast agents. ACS Macro Lett 8(4):473–478PubMedPubMedCentralGoogle Scholar
  35. 35.
    Bose A, Jana S, Saha A, Mandal TK (2017) Amphiphilic polypeptide-polyoxazoline graft copolymer conjugate with tunable thermoresponsiveness: synthesis and self-assembly into various micellar structures in aqueous and nonaqueous media. Polymer 110:12–24Google Scholar
  36. 36.
    Kudryavtseva AA, Kurlykin MP, Tarabukina EB, Tenkovtsev AV, Filippov AP (2017) Behavior of thermosensitive graft-copolymer with aromatic polyester backbone and poly-2-ethyl-2-oxazoline side chains in aqueous solutions. Int J Polym Anal Char 22:526–533Google Scholar
  37. 37.
    Filippov AP, Tarabukina EB, Simonova MA, Kirila TU, Fundueanu G, Harabagiu V, Constantin M, Popescu I (2015) Synthesis and investigation of double stimuli-responsive behavior of N-isopropylacrylamide and maleic acid copolymer. J Macromol Sci Part B: Phys 54:1105–1121. CrossRefGoogle Scholar
  38. 38.
    Schärtl W (2007) Light scattering from polymer solutions and nanoparticle dispersions. Springer-Verlag, BerlinGoogle Scholar
  39. 39.
    Kocak G, Tuncer C, Bűtűn V (2017) pH-responsive polymers. Polym Chem 8:144–176Google Scholar
  40. 40.
    Amirova A, Rodchenko S, Milenin S, Tatarinova E, Kurlykin M, Tenkovtsev A, Filippov A (2017) Influence of a hydrophobic core on thermoresponsive behavior of dendrimer-based star-shaped poly(2-isopropyl-2-oxazoline) in aqueous solutions. J Polym Res 24(8):124Google Scholar
  41. 41.
    Kirile TY, Tobolina AI, Elkina AA, Kurlykin MP, Ten’kovtsev AV, Filippov AP (2018) Self-assembly processes in aqueous solutions of heat-sensitive star-shaped poly-2-ethyl-2-oxazoline. Fibre Chemistry 50(3):248–251Google Scholar
  42. 42.
    Katsumoto Y, Tsuchiizu A, Qiu XP, Winnik FM (2012) Dissecting the mechanism of the heat-induced phase separation and crystallization of poly(2-isopropyl-2-oxazoline) in water through vibrational spectroscopy and molecular orbital calculations. Macromolecules 45:3531–3541Google Scholar
  43. 43.
    Lin PY, Clash C, Pearce EM, Kwei TK, Aponte MA (1988) Solubility and miscibility of poly (ethyl oxazoline). J Polym Sci Part B: Polym Physics 26:603–619Google Scholar
  44. 44.
    Wang CH, Hsiue GH (2002) Synthesis and characterization of temperature- and pH-sensitive hydrogels based on poly(2-ethyl-2-oxazoline) and poly(D,L-lactide). J Polym Sci Part A: Polym Chem 40:1112–1121Google Scholar
  45. 45.
    Li J, Zhou Y, Li C, Wang D, Gao Y, Zhang C, Zhao L, Li Y, Liu Y, Li X (2015) Poly(2-ethyl-2-oxazoline)–doxorubicin conjugate-based dual endosomal pH-sensitive micelles with enhanced antitumor efficacy. Bioconjug Chem 26:110–119PubMedGoogle Scholar
  46. 46.
    Cagli E, Yildirim E, Yang S, Erel-Goktepe I (2019) An experimental and computational approach to pH-dependent self-aggregation of poly(2-isopropyl-2-oxazoline). J Polym Sci Part B: Polym Physics 57:210-221Google Scholar
  47. 47.
    Amirova A, Rodchenko S, Filippov A (2016) Time dependence of the aggregation of star-shaped poly(2-isopropyl-2-oxazolines) in aqueous solutions. J Polym Res 23:221. CrossRefGoogle Scholar
  48. 48.
    Tarabukina EB, Simonova MA, Bucatariu S, Harabagiu V, Fundueanu G, Filippov AP (2015) Behavior of thermo- and pH-responsive copolymer of N-isopropylacrylamide and maleic acid in aqueous solutions. Int J Polym Anal Char 21:11–17Google Scholar
  49. 49.
    Filippov AP, Belyaeva EV, Zakharova NV, Sasina AS, Ilgach DM, Meleshko TK, Yakimansky AV (2015) Double stimuli-responsive behavior of graft copolymer with polyimide backbone and poly(N,N-dimethylaminoethyl methacrylate) side chains. Colloid Polym Sci 293:555–565Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Alexander Filippov
    • 1
  • Elena Tarabukina
    • 1
    Email author
  • Alisa Kudryavtseva
    • 1
  • Emil Fatullaev
    • 2
  • Mikhail Kurlykin
    • 1
  • Andrey Tenkovtsev
    • 1
  1. 1.Institute of Macromolecular CompoundsRussian Academy of SciencesSaint PetersburgRussia
  2. 2.Saint Petersburg National Research University of Information Technologies, Mechanics and OpticSaint PetersburgRussia

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