Multifunctional ferrofluid-infused surfaces with reconfigurable multiscale topography

Journal Article · Mon Jun 25 00:00:00 EDT 2018 · Nature (London)

DOI:https://doi.org/10.1038/s41586-018-0250-8· OSTI ID:1504366

Wang, Wendong ^[1]; Timonen, Jaakko V. I. ^[2]; Carlson, Andreas ^[3]; Drotlef, Dirk-Michael ^[4]; Zhang, Cathy T. ^[5]; Kolle, Stefan ^[6]; Grinthal, Alison ^[6]; Wong, Tak-Sing ^[7]; Hatton, Benjamin ^[8]; Kang, Sung Hoon ^[9]; Kennedy, Stephen ^[10]; Chi, Joshua ^[11]; Blough, Robert Thomas ^[12]; Sitti, Metin ^[4]; Mahadevan, L. ^[13]; Aizenberg, Joanna ^[14]

---

1. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Max Planck Inst. for Intelligent Systems, Stuttgart (Germany)
2. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences; Aalto Univ. School of Science, Espoo (Finland). Dept. of Applied Physics
3. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Univ. of Oslo (Norway). Department of Mathematics, Mechanics Division
4. Max Planck Inst. for Intelligent Systems, Stuttgart (Germany)
5. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering
6. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences
7. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Pennsylvania State Univ., University Park, PA (United States). Dept of Mechanical and Nuclear Engineering and the Materials Research Inst.
8. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Univ. of Toronto, ON (Canada). Materials Science and Engineering
9. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Mechanical Engineering, Hopkins Extreme Materials Inst.
10. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering; Univ. of Rhode Island, Kingston, RI (United States). Dept. of Biomedical and Chemical Engineering
11. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, Dept. of Chemistry and Chemical Biology; Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemical and Biomolecular Engineering
12. Harvard Univ., Cambridge, MA (United States). Wyss Inst. for Biologically Inspired Engineering
13. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering, Kavli Inst. for Bionano Science and Technology
14. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences, and Wyss Inst. for Biologically Inspired Engineering, Dept. of Chemistry and Chemical Biology, Kavli Inst. for Bionano Science and Technology

Developing adaptive materials with geometries that change in response to external stimuli provides fundamental insights into the links between the physical forces involved and the resultant morphologies and creates a foundation for technologically relevant dynamic systems. In particular, reconfigurable surface topography as a means to control interfacial properties has recently been explored using responsive gels, shape-memory polymers, liquid crystals and hybrid composites, including magnetically active slippery surfaces. However, these designs exhibit a limited range of topographical changes and thus a restricted scope of function. Here we introduce a hierarchical magneto-responsive composite surface, made by infiltrating a ferrofluid into a microstructured matrix (termed ferrofluid-containing liquid-infused porous surfaces, or FLIPS). We demonstrate various topographical reconfigurations at multiple length scales and a broad range of associated emergent behaviours. An applied magnetic-field gradient induces the movement of magnetic nanoparticles suspended in a viscous fluid, which leads to microscale flow of this ferrofluid first above and then within the microstructured surface. This redistribution changes the initially smooth surface of the ferrofluid (which is immobilized by the porous matrix through capillary forces) into various multiscale hierarchical topographies shaped by the size, arrangement and orientation of the confining microstructures in the magnetic field. We analyse the spatial and temporal dynamics of these reconfigurations theoretically and experimentally as a function of the balance between capillary and magnetic pressures and of the geometric anisotropy of the FLIPS system. Several interesting functions at three different length scales are demonstrated: self-assembly of colloidal particles at the micrometre scale; regulated flow of liquid droplets at the millimetre scale; and switchable adhesion and friction, liquid pumping and removal of biofilms at the centimetre scale. We envision that FLIPS could be used as part of integrated control systems for the manipulation and transport of matter, thermal management, microfluidics and fouling-release materials.

• Research Organization: Harvard Univ., Cambridge, MA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0005247
• OSTI ID: 1504366
• Journal Information: Nature (London), Vol. 559, Issue 7712; ISSN 0028-0836
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE