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conferenceseries.com
March 20-22, 2017 Orlando, USA
3rd International Conference on
Smart Materials & Structures
Volume 6, Issue 2 (Suppl) J Material Sci Eng
ISSN: 2169-0022 JME, an open access journal Smart Materials 2017
March 20-22, 2017
Fabrication of hierarchical structures using electrospinning for dry adhesive applications
Avinash Baji and Rahul Sahay
Singapore University of Technology and Design, Singapore
In this study, hierarchical structures for dry-adhesive applications were fabricated using electrospinning combined with template
wetting method. Briefly, in the first step, electrospinning technique was used to produce micron sized fibers which were directly
deposited on porous anodized aluminum oxide (AAO) template. Following this step, the setup consisting of the AAO template along
with the fibers was heated above the glass transition temperature of polymer. This enabled the flow of polymer within the porous
channels and resulted in the growth of nanometer sized pillars on the surface of the fibers. Based on this fabrication technique, we
produced hierarchical structures using two different polymeric systems, viz. poly(methyl methacrylate) (PMMA) and poly(vinylidene
fluoride) (PVDF). A representative scanning electron microscopy (SEM) image of the fibers is shown in Figure-1. The SEM image
shows that this approach led to the growth of sub-nano structures on the surface of the fibers. These samples were used to investigate
the normal as well as shear adhesion behavior of hierarchical structures. The normal adhesion was characterized using a nanoindenter.
A flat circular indenter tip (diameter=10 µm) was used to indent the surface of the samples and then retracted back. The pull-off
required to separate the indenter tip from the samples was recorded. This pull-off force gave an indication of its normal adhesion.
Similarly, the samples were finger pressed onto sandpaper with varying degree of roughness. The samples were then pulled in shear
and the shear adhesion force was characterized. Fibers without any surface structures were also tested and their adhesion behavior
was compared with that of hierarchical samples. The samples with surface nanostructures exhibited increased pull-off force compared
to neat control samples due to its improved van der Waals interactions.
Biography
Avinash Baji focuses on bio-inspired materials research using electrospun polymer fibers. His current research interests include fabrication of electrospun fibers for dry
adhesion applications. He aims to mimic the geometry and adhesive mechanisms of natural materials using electrospinning enabled techniques. He has authored over 35
journal articles with additional papers in conference proceedings.
Avinash Baji et al., J Material Sci Eng 2017, 6:2 (Suppl)