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Tunable and Magnetic Thiol-ene Micropillar Arrays
Anas Al-Azawi1, Zoran Cenev2, Topi Tupasela1
1Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076, Aalto, Espoo, Finland.
Macromolecular Rapid Communications
|November 29, 2019
Summary
Researchers developed magnetic, flexible micropillars that bend in response to magnetic fields. These responsive surfaces enable tunable functionalities like controlled adhesion and droplet manipulation, inspired by biological cilia.
Area of Science:
- Materials Science
- Surface Science
- Microfluidics
Background:
- Tunable and responsive surfaces are crucial for developing advanced functionalities.
- Biological systems, like respiratory cilia, offer inspiration for micro-scale actuation and surface properties.
Purpose of the Study:
- To fabricate magnetically responsive, flexible micropillars inspired by biological cilia.
- To investigate the actuation, elastic properties, and surface modifiability of these micropillars.
- To demonstrate potential applications in controlled adhesion, droplet manipulation, and particle transport.
Main Methods:
- Fabrication of periodic arrays of flexible and magnetic thiol-ene micropillars.
- Actuation studies using external magnetic fields and an electromagnetic needle.
- Characterization of pillar responsiveness and elastic properties by varying thiol-ene crosslinking density.
- Surface modification via UV-assisted grafting of self-assembled monolayers and covalent bonding of nanoparticles.
- Wettability studies and contact angle hysteresis measurements.
Main Results:
- Omnidirectional collective bending of the pillar array in a magnetic field was demonstrated.
- Local non-contact actuation of single pillars was achieved, revealing tunable elastic properties.
- Suitable thiol-ene components and ratios for flexible and stiff magnetic micropillars were identified.
- Modified micropillars exhibited resistance to collapse and low contact angle hysteresis.
- Demonstrated controlled motion of water droplets and transport of polyethylene microspheres.
Conclusions:
- Magnetically responsive thiol-ene micropillars offer a versatile platform for tunable surface functionalities.
- The developed system mimics biological cilia for micro-scale actuation and manipulation.
- Surface modification strategies enable tailored wettability and robust performance for droplet and particle transport applications.
