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Reversible phase transitions in polymer gels induced by radiation forces

Abstract

Many polymer gels undergo reversible, discontinuous volume changes in response to changes in the balance between repulsive intermolecular forces that act to expand the polymer network and attractive forces that act to shrink it. Repulsive forces are usually electrostatic or hydrophobic in nature, whereas attraction is mediated by hydrogen bonding or van der Waals interactions. The competition between these counteracting forces, and hence the gel volume1,2,3, can thus be controlled by subtle changes in parameters such as pH (ref. 4), temperature5, solvent composition6 or gel composition7. Here we describe a more direct influence on this balance of forces, by showing that the radiation force generated by a focused laser beam induces reversible shrinkage in polymer gels. Control experiments confirm that the laser-induced volume phase transitions are due to radiation forces, rather than local heating, modifying the weak interactions in the gels, in agreement with previous observations of light-induced chain association in polymer solutions8,9. We find that, owing to shear-relaxation processes10, gel shrinkage occurs up to several tens of micrometres away from the irradiation spot, raising the prospect that the combination of stimuli-responsive polymer gels and laser light might lead to new gel-based systems for applications such as actuating or sensing.

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Figure 1: The volume phase transition in gels.
Figure 2: The power dependence of gel-rod collapse.
Figure 3: Temperature dependence of the diameter of rods of doped and undoped PNIPAM gel.
Figure 4: Volume phase transition of PNIPAM gel in D2O.

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References

  1. Schild, H. G. Poly(N-isopropylacrylamide): experiment, theory and applications. Prog. Polym. Sci. 17, 163–249 (1992).

    Article  CAS  Google Scholar 

  2. Ilmain, F., Tanaka, T. & Kokufuta, E. Volume transition in a gel driven by hydrogen bonding. Nature 349, 400–401 (1991).

    Article  ADS  CAS  Google Scholar 

  3. Takeoka, Y. et al. First order phase transition and evidence for frustrations in polyampholytic gels. Phys. Rev. Lett. 82, 4863–4865 (1999).

    Article  ADS  CAS  Google Scholar 

  4. Annaka, M. & Tanaka, T. Multiple phases of polymer gels. Nature 355, 430–432 (1992).

    Article  ADS  CAS  Google Scholar 

  5. Suzuki, A. & Tanaka, T. Phase transition in polymer gels induced by visible light. Nature 346, 345 –347 (1990).

    Article  ADS  CAS  Google Scholar 

  6. Hirokawa, Y. & Tanaka, T. Volume phase transition in a non-ionic gel. J. Chem. Phys. 81, 6379– 6380 (1984).

    Article  ADS  Google Scholar 

  7. Hirotsu, S., Hirokawa, Y. & Tanaka, T. Volume-phase transition of ionized N-isopropylacrylamide gels. J. Chem. Phys. 87, 1392– 1395 (1987).

    Article  ADS  CAS  Google Scholar 

  8. Smith, T. A., Hotta, J., Sasaki, K., Masuhara, H. & Itoh, Y. Photon pressure-induced association of nanometer-sized polymer chains in solutions. J. Phys. Chem. B 103, 1660–1663 (1999).

    Article  CAS  Google Scholar 

  9. Hofkens, J., Hotta, J., Sasaki, K., Masuhara, H. & Iwai, K. Molecular assembling by the radiation pressure of a focused laser beam: poly(N-isopropylacrylamide) in aqueous solution. Langmuir 13, 414–419 ( 1997).

    Article  CAS  Google Scholar 

  10. Shibayama, M. & Tanaka, T. Volume phase transition and related phenomena of polymer gels. Adv. Polym. Sci. 109, 1–62 (1993).

    Article  CAS  Google Scholar 

  11. Svoboda, K. & Block, S. M. Biological applications of optical forces. Annu. Rev. Biophys. Biomol. Struct. 23, 247–285 (1994).

    Article  CAS  Google Scholar 

  12. Misawa, H. & Juodkazis, S. Photophysics and photochemistry of a laser manipulated microparticle. Prog. Polym. Sci. 24, 665–697 (1999).

    Article  CAS  Google Scholar 

  13. Juodkazis, S., Shikata, M., Takahashi, T., Matsuo, S. & Misawa, H. Fast optical switching by a laser-manipulated microdroplet of liquid crystal. Appl. Phys. Lett. 74 , 3627–3629 (1999).

    Article  ADS  CAS  Google Scholar 

  14. Ashkin, A. Acceleration and trapping of particles by radiation pressure. Phys. Rev. Lett. 24, 156–159 (1970).

    Article  ADS  CAS  Google Scholar 

  15. Shen, Y. R. The Principles of Nonlinear Optics 366–379 (Wiley & Sons, New York, 1984).

    Google Scholar 

  16. Ishikawa, M., Misawa, H., Kitamura, N., Fujisawa, R. & Masuhara, H. Infrared laser-induced photo-thermal phase transition of an aqueous poly(N-isopropylacrylamide) solution in the micrometer dimension. Bull. Chem. Soc. Jpn 69, 59– 66 (1996).

    Article  CAS  Google Scholar 

  17. Schild, H. G. & Tirrell, D. A. Microcalorimetric detection of lower critical solution temperatures in aqueous polymer solutions. J. Phys. Chem. 94, 4352–4356 (1990).

    Article  CAS  Google Scholar 

  18. Fritze, M., Stern, M. B. & Wyatt, P. W. Laser-fabricated glass microlens arrays. Opt. Lett. 23, 1441–143 (1998).

    Article  Google Scholar 

  19. Strobl, G. R. The Physics of Polymers 63–128 (Springer, Berlin, 1997).

    Google Scholar 

  20. Hu, Z., Zang, X. & Li, Y. Synthesis and application of modulated polymer gels. Science 269, 525–527 (1995).

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

This present work was supported in part by a grant under Priority Area Research “Photoreaction Dynamics” from the Ministry of Education, Science, Sports and Culture of Japan, by a NEDO (New Energy Industrial Technology Development Organization) regional consortium project ”Development of Ultrasensitive Micro-Integrated Analysis Systems”, and by the Satellite Venture Business Laboratory of the University of Tokushima.

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Correspondence to Hiroaki Misawa.

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Juodkazis, S., Mukai, N., Wakaki, R. et al. Reversible phase transitions in polymer gels induced by radiation forces . Nature 408, 178–181 (2000). https://doi.org/10.1038/35041522

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