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.

Soft dendritic microparticles with unusual adhesion and structuring properties

Abstract

The interplay between morphology, excluded volume and adhesivity of particles critically determines the physical properties of numerous soft materials and coatings1,2,3,4,5,6. Branched particles2 or nanofibres3, nanofibrillated cellulose4 or fumed silica5 can enhance the structure-building abilities of colloids, whose adhesion may also be increased by capillarity or binding agents6. Nonetheless, alternative mechanisms of strong adhesion found in nature involve fibrillar mats with numerous subcontacts (contact splitting)7,8,9,10,11 as seen in the feet of gecko lizards and spider webs12,13,14,15,16,17. Here, we describe the fabrication of hierarchically structured polymeric microparticles having branched nanofibre coronas with a dendritic morphology. Polymer precipitation in highly turbulent flow results in microparticles with fractal branching and nanofibrillar contact splitting that exhibit gelation at very low volume fractions, strong interparticle adhesion and binding into coatings and non-woven sheets. These soft dendritic particles also have potential advantages for food, personal care or pharmaceutical product formulations.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Fabrication and properties of soft dendritic colloidal microparticles.
Fig. 2: Conditions for dendricolloid formation.
Fig. 3: Adhesion characteristics of soft dendritic colloidal microparticles.
Fig. 4: Structuring capability of soft dendricolloids in liquid suspensions.

Data availability

All data, experimental details and supplemental analysis are available in the main text or the supplementary material. Further related raw data images and files are available on request from the authors.

References

  1. 1.

    Alargova, R. G., Bhatt, K. H., Paunov, V. N. & Velev, O. D. Scalable synthesis of a new class of polymer microrods by a liquid–liquid dispersion technique. Adv. Mater. 16, 1653–1657 (2004).

    CAS  Article  Google Scholar 

  2. 2.

    Bahng, J. H. et al. Anomalous dispersions of ‘hedgehog’ particles. Nature 517, 596–599 (2015).

    CAS  Article  Google Scholar 

  3. 3.

    Zhu, J. Brached aramid nanofibers. Angew. Chem. Int. Ed. 56, 11744–11748 (2017).

    CAS  Article  Google Scholar 

  4. 4.

    Pääkkö, M. et al. Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenization for nanoscale cellulose fibrils and strong gels. Biomacromolecules 8, 1934–1941 (2007).

    Article  Google Scholar 

  5. 5.

    Khan, S. A. & Zoeller, N. J. Dynamic rheological behavior of flocculated fumed silica suspensions. J. Rheol. 37, 1225–1235 (1993).

    CAS  Article  Google Scholar 

  6. 6.

    Koos, E. & Willenbacher, N. Capillary forces in suspension rheology. Science 331, 897–900 (2011).

    CAS  Article  Google Scholar 

  7. 7.

    Cadirov, N., Booth, J. A., Turner, K. L. & Israelachvili, J. N. Influence of humidity on grip and release adhesion mechanisms for gecko-inspired microfibrillar surfaces. ACS Appl. Mater. Interfaces 9, 14497–14505 (2017).

    CAS  Article  Google Scholar 

  8. 8.

    King, D. R., Bartlett, M. D., Gilman, C. A., Irschick, D. J. & Crosby, A. J. Creating gecko-like adhesives for ‘real world’ surfaces. Adv. Mater. 26, 4345–4351 (2014).

    CAS  Article  Google Scholar 

  9. 9.

    Ge, L., Sethi, S., Ci, L., Ajayan, P. M. & Dhinojwala, A. Carbon nanotube-based synthetic gecko tapes. Proc. Natl Acad. Sci. USA 104, 10792–10795 (2007).

    CAS  Article  Google Scholar 

  10. 10.

    Kwak, M. K., Jeong, H. E. & Suh, K. Y. Rational design and enhanced biocompatibility of a dry adhesive medical skin patch. Adv. Mater. 23, 3949–3953 (2011).

    CAS  Article  Google Scholar 

  11. 11.

    Qu, L., Dai, L., Stone, M., Xia, Z. & Wang, Z. L. Carbon nanotube arrays with strong shear binding-on and easy normal lifting-off. Science 322, 238–243 (2008).

    CAS  Article  Google Scholar 

  12. 12.

    Autumn, K. et al. Adhesive force of a single gecko foot-hair. Nature 405, 681–685 (2000).

    CAS  Article  Google Scholar 

  13. 13.

    Autumn, K. et al. Evidence for van der Waals adhesion in gecko setae. Proc. Natl Acad. Sci. USA 99, 12252–12256 (2002).

    CAS  Article  Google Scholar 

  14. 14.

    Tian, Y. et al. Adhesion and friction in gecko toe attachment and detachment. Proc. Natl Acad. Sci. USA 103, 19320–19325 (2006).

    CAS  Article  Google Scholar 

  15. 15.

    Sahni, V., Harris, J., Blackledge, T. A. & Dhinojwala, A. Cobweb-weaving spiders produce different attachment discs for locomotion and prey capture. Nat. Commun. 3, 1106 (2012).

    Article  Google Scholar 

  16. 16.

    Kamperman, M., Kroner, E., Del Campo, A., McMeeking, R. M. & Arzt, E. Functional adhesive surfaces with ‘Gecko’ effect: the concept of contact splitting. Adv. Eng. Mater. 12, 335–348 (2010).

    CAS  Article  Google Scholar 

  17. 17.

    Hawthorn, A. C. & Opell, B. D. van der waals and hygroscopic forces of adhesion generated by spider capture threads. J. Exp. Biol. 206, 3905–3911 (2003).

    Article  Google Scholar 

  18. 18.

    Smoukov, S. K. et al. Scalable liquid shear-driven fabrication of polymer nanofibers. Adv. Mater. 27, 2642–2647 (2015).

    CAS  Article  Google Scholar 

  19. 19.

    Haase, M. F., Stebe, K. J. & Lee, D. Continuous fabrication of hierarchical and asymmetric bijel microparticles, fibers, and membranes by solvent transfer-induced phase separation (STRIPS). Adv. Mater. 27, 7065–7071 (2015).

    CAS  Article  Google Scholar 

  20. 20.

    Procaccia, I. Fractal structures in turbulence. J. Stat. Phys. 36, 649–663 (1984).

    Article  Google Scholar 

  21. 21.

    Bhushan, B. Adhesion of multi-level hierarchical attachment systems in gecko feet. J. Adhes. Sci. Technol. 21, 1213–1258 (2007).

    CAS  Article  Google Scholar 

  22. 22.

    Arzt, E., Gorb, S. & Spolenak, R. From micro to nano contacts in biological attachment devices. Proc. Natl Acad. Sci. USA 100, 10603–10606 (2003).

    CAS  Article  Google Scholar 

  23. 23.

    Raut, H. K. et al. Gecko-inspired dry adhesive based on micro-nanoscale hierarchical arrays for application in climbing devices. ACS Appl. Mater. Interfaces 10, 1288–1296 (2018).

    CAS  Article  Google Scholar 

  24. 24.

    Huber, G. et al. Evidence for capillarity contributions to gecko adhesion from single spatula nanomechanical measurements. Proc. Natl Acad. Sci. USA 102, 16293–16296 (2005).

    CAS  Article  Google Scholar 

  25. 25.

    Israelachvili, J. N. Intermolecular and Surface Forces (Elsevier, 2011).

  26. 26.

    Johnson, K. L., Kendall, K. & Roberts, A. D. Surface energy and the contact of elastic solids. Proc. R. Soc. A 324, 301–313 (1971).

    CAS  Article  Google Scholar 

  27. 27.

    Lau, K. K. S. et al. Superhydrophobic carbon nanotube forests. Nano Lett. 3, 1701–1705 (2003).

    CAS  Article  Google Scholar 

  28. 28.

    Buhleier, E., Wehner, W. & Vögtle, F. ‘Cascade’- and ‘nonskid-chain-like’ syntheses of molecular cavity topologies. Synthesis 1978, 155–158 (1978).

    Article  Google Scholar 

  29. 29.

    Hawker, C. J. & Fréchet, J. M. J. Preparation of polymers with controlled molecular architecture. a new convergent approach to dendritic macromolecules. J. Am. Chem. Soc. 112, 7638–7647 (1990).

    CAS  Article  Google Scholar 

  30. 30.

    Astruc, D., Boisselier, E. & Ornelas, C. Dendrimers designed for functions: from physical, photophysical, and supramolecular properties to applications in sensing, catalysis, molecular electronics, photonics, and nanomedicine. Chem. Rev. 110, 1857–1959 (2010).

    CAS  Article  Google Scholar 

  31. 31.

    Butt, H. & Kappl, M. Surface and Interfacial Forces. (John Wiley & Sons, Weinheim, 2009).

  32. 32.

    Chaudhury, M. K., Weaver, T., Hui, C. Y. & Kramer, E. J. Adhesive contact of cylindrical lens and a flat sheet. J. Appl. Phys. 80, 30–37 (1996).

    CAS  Article  Google Scholar 

  33. 33.

    Spolenak, R., Gorb, S., Gao, H. & Arzt, E. Effects of contact shape on the scaling of biological attachments. Proc. R. Soc. A 461, 305–319 (2005).

    Article  Google Scholar 

Download references

Acknowledgements

This study was supported by grants from US National Science Foundation, no. CMMI-1825476 and partially no. CBET-1604116. We also thank NC State University for support through 2017 Chancellors Innovation Fund Award and Unilever Research. We thank L. Hsiao, S. Khan and M. Dickey for discussions and generously providing their rheometer, goniometer and mechanical testing machine facilities. We thank the Cellular and Molecular Imaging Facility at NC State University for their help with confocal imaging supported by the National Science Foundation (grant no. DBI-1624613).

Author information

Affiliations

Authors

Contributions

The initial discovery of the dendricolloid formation was made by S.R. and O.D.V. The experimental design and data analysis were done by O.D.V., S.R., A.H.W., R.S.B. and S.D.S. The experimental laboratory work on dendricolloid synthesis and characterization was performed by S.R., A.H.W., and R.S.B. S.R. and O.D.V. were primary writers of the manuscript, and O.D.V. was the principal investigator. All authors discussed the results and provided feedback on the manuscript.

Corresponding author

Correspondence to Orlin D. Velev.

Ethics declarations

Competing interests

S.R. and O.D.V. are inventors on a patent application submitted by NC State University, which covers synthesis and properties of fractal polymer colloids.

Additional information

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

Supplementary information

Supplementary Information

Supplementary text, Video 1 legend, Figs. 1–14, Table 1 and references.

Supplementary Video 1

Three-dimensional confocal reconstruction video of a soft dendritic microparticle.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Roh, S., Williams, A.H., Bang, R.S. et al. Soft dendritic microparticles with unusual adhesion and structuring properties. Nat. Mater. 18, 1315–1320 (2019). https://doi.org/10.1038/s41563-019-0508-z

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing