Braun Group People
Dr. Jeong-Ho Park
Post Doctoral Researcher, Materials Science and Engineering
Post Doctoral Researcher, Materials Science and Engineering, Gwangju Institute Science and Technology (GIST), Korea (2006-2007)
M.S. in Materials Science and Engineering, Gwangju Institute Science and Technology (GIST), Korea (2002)
B.S. in Materials Science and Engineering, Pusan national University, Korea (1999)
Self-healing coating based on electro-spinning technique
Autonomic healing polymeric materials exhibit the ability to repair themselves and recover functionalities using the resources inherently available to them. Recent studies on self-healing polymers have demonstrated repair of mechanical damage of bulk systems as well as dramatic improvement in the fatigue life. Self-healing coatings which autonomically repair and prevent corrosion of the underlying substrate are of particular interest. The majority of previously reported healing systems, however, have chemical and mechanical limitations preventing their use as coatings application.
Here I’m working on a new approach to self-healing polymer coating systems based on the electro-spinning of healing agent encapsulated fibrous structures, and demonstrate its effectiveness for both model and industrially important coating systems. Using electro-spinning, liquids, such as a healing agent, can be encapsulated into core-shell fibers and these fibers can be coated on a substrate in a form which is attractive for a self-healing coating. In electro-spinning process, electro-hydro-dynamic forces smoothly stretches the fluid interface to form very thin electrified coaxial jets. Using the electro-spinning with a coaxial nozzle to form 1D core (healing agents) – sheath fiber structures, the liquid healing agent becomes encapsulated in capsules that are randomly distributed along the polymer nano-, micro- scaled fibers as shown in Fig. 1.
This 1D core-shell fiber structure produced by two-fluid electro-spinning may be advantageous for self-healing because more healing agent may be accessed due to their higher percolation pathway compared to 0D core-shell spherical particles system. The process itself is an improvement over solution-based encapsulations because it is an easy and simple process, has versatile structure controllability, has extremely high throughput capability and has excellent processability for large area coatings.
Figure 1. Schematic illustration of the setup for electro-spun fibers having core/sheath structure. (a) The spinneret was manufactured from two coaxial capillaries, through which healing agent (core) and polymer solution(sheath) were simultaneously ejected to form a continuous coaxial jet. Two different SEM images of healing agent encapsulated fibrous structures; (b) beads on string and (c) smooth tube, respectively. Inset figure of Fig. (b) and (c) is schematic of corresponding core/sheath structures, respectively.
Professor Paul Braun • Phone: +1.217.244.7293 • Fax: +1.217.333.2736 • Email: pbraun@illinois.edu
Department of Materials Science and Engineering • University of Illinois at Urbana-Champaign