Revealing nanoscale chemical heterogeneity at the surface of water-based coatings prepared from urethane–acrylic hybrids by photo-induced force microscopy

  • Qi ChenEmail author
  • Saskia van der Slot
  • Sven Kreisig
  • Mingwen Tian
  • Ron Peters
  • Joachim LoosEmail author


The surface chemical composition of water-based coatings prepared from urethane–acrylic hybrids or blends is investigated using infrared photo-induced force microscopy. By monitoring the interaction between the optically driven molecular dipole and its mirror image in a metal-coated tip, detailed information of the chemical composition at the coating surface down to 20 nm local resolution in all three dimensions is obtained. The film matrix of the coatings is determined to be the polyurethane while the polyacrylate particles are dispersed in the film. Phase separation of the two materials is found to be at a much smaller length scale in hybrid coatings compared to that in blends. This is because the acrylic monomers are introduced during the dispersion of the polyurethane in the synthesis of the hybrid particles, in contrast to the simple mixing of the two polymer particles in the case of the blends. Photo-induced force microscopy proved to be a powerful tool in the identification and visualization of different chemical species of coating surfaces at the nanoscale.


Urethane–acrylic hybrids Atomic force microscopy Nanoscale chemical imaging Water-based coatings Photo-induced force microscopy 



The authors would like to thank DSM for permission to publish this paper. Sung Park, Derek Nowak from Molecular Vista and Anne Muller from Anfatec Instruments are kindly acknowledged for granting access to the PiFM setup and the fruitful discussions.


  1. 1.
    Keddie, JL, Routh, AF, Fundamentals of Latex Film Formation. Springer, Dordrecht (2010)CrossRefGoogle Scholar
  2. 2.
    Schuler, B, Baumstark, R, Kirsch, S, Pfau, A, Sandor, M, Zosel, A, “Structure and properties of multiphase particles and their impact on the performance of architectural coatings.” Prog. Org. Coat., 40 139–150 (2000)CrossRefGoogle Scholar
  3. 3.
    Patricio, PSO, Sales, DJA, Silva, GG, Windmöller, D, Machado, JC, “Effect of blend composition on microstructure, morphology, and gas permeability in PU/PMMA blends.” J. Membr. Sci., 271 177–185 (2006)CrossRefGoogle Scholar
  4. 4.
    Tennebroek, R, van der Hoeven-van Casteren, I, Swaans, R, van der Slot, S, Stals, PJM, Tuijtelaars, B, Koning, C, “Water-based polyurethane dispersions.” Polym. Int., (2018). Google Scholar
  5. 5.
    Mequanint, K, Sanderson, R, Pasch, H, “Phosphated polyurethane–acrylic dispersions: synthesis, rheological properties and wetting behaviour.” Polymer, 43 5341–5346 (2002)CrossRefGoogle Scholar
  6. 6.
    Kukanja, D, Golob, J, Krajnc, M, “Kinetic investigations of acrylic–polyurethane composite latex.” J. Appl. Polym. Sci., 84 2639–2649 (2002)CrossRefGoogle Scholar
  7. 7.
    Kim, IH, Shin, JS, Cheong, IW, Kim, JI, Kim, JH, “Seeded emulsion polymerization of methyl methacrylate using aqueous polyurethane dispersion: effect of hard segment on grafting efficiency.” Colloids Surf A Physicochem Eng Asp, 207 169–176 (2002)CrossRefGoogle Scholar
  8. 8.
    Oprea, S, Vlad, S, Stanciu, A, Ciobanu, C, Macoveanu, M, “Syntheses and characterization of poly(urethaneureaacrylate)s.” Eur. Polym. J., 36 373–378 (2000)CrossRefGoogle Scholar
  9. 9.
    Kim, BK, Shin, JH, “Modification of waterborne polyurethane by forming latex interpenetrating polymer networks with acrylate rubber.” Colloid Polym. Sci., 280 716–724 (2003)CrossRefGoogle Scholar
  10. 10.
    Overbeek, A, “Polymer heterogeneity in waterborne coatings.” J. Coat. Technol. Res., 7 1–21 (2010)CrossRefGoogle Scholar
  11. 11.
    Xue, L, Li, W, Hoffmann, GG, Goossens, JGP, Loos, J, de With, G, “High-resolution chemical identification of polymer blend thin films using tip-enhanced Raman mapping.” Macromolecules, 44 2852 (2011)CrossRefGoogle Scholar
  12. 12.
    Dazzi, A, Prazeres, R, Glotin, F, Ortega, JM, “Local infrared microspectroscopy with subwavelength spatial resolution with an atomic force microscope tip used as a photothermal sensor.” Opt. Lett., 30 2388 (2005)CrossRefGoogle Scholar
  13. 13.
    Hillenbrand, R, Taubner, T, Keilmann, F, “Phonon-enhanced light–matter interaction at the nanometre scale.” Nature, 418 159 (2002)CrossRefGoogle Scholar
  14. 14.
    Nowak, D, Morrison, W, Wickramasinghe, HK, Jahng, J, Potma, EO, Wan, L, Ruiz, R, Albrecht, TR, Schmidt, K, Frommer, J, Sanders, DP, Park, S, “Nanoscale chemical imaging by photoinduced force microscopy.” Sci. Adv., 2 e1501571 (2016)CrossRefGoogle Scholar
  15. 15.
    Chen, Q, Scheerder, J, de Vos, K, Tak, R, “Influence of cosolvent retention on film formation and surface mechanical properties of water based acrylic coatings by atomic force microscopy.” Prog. Org. Coat., 102 231–238 (2017)CrossRefGoogle Scholar
  16. 16.
    Dieterich, D, “Aqueous emulsions, dispersions and solutions of polyurethanes; synthesis and properties.” Prog. Org. Coat., 9 281 (1981)CrossRefGoogle Scholar
  17. 17.
    Jahng, J, Ladani, FT, Khan, RM, Potma, EO, “Photo-induced force for spectroscopic imaging at the nanoscale.” Proc. SPIE, 9764 97641J-1 (2016)Google Scholar

Copyright information

© American Coatings Association 2019

Authors and Affiliations

  1. 1.DSM Coating ResinsWaalwijkThe Netherlands
  2. 2.DSM Materials Science CenterGeleenThe Netherlands

Personalised recommendations