Hierarchical Assembly of Polymeric Nanofibers for Advanced Material Applications

Polymer nanofibers are gaining importance due to their wide applicability in diverse fields, such as tissue engineering, fuel cells, photonics and sensors. For these applications, manufacturing aligned polymer nanofibers with precisely controlled morphology and well characterized mechanical properties in a bottom up configuration is essential. In this work, we developed an isodiametric design space for fabrication of aligned polystyrene nanofibers (diameter 60-800nm) using non-electrospinning Spinneret based Tunable Engineered Parameter (STEP) technique. By adjusting the processing parameters such as relative humidity, solvent volatility and polarity, porous polymer tubes are demonstrated having large specific surface areas. Combining STEP with sol-gel process, aligned inorganic nanofibers, such as Titanium Oxide (TiO2) with varied morphologies can be conveniently obtained. Mechanical properties of aligned polymer nanofibers (diameter from 50nm to several hundred nanometers) with fixed-fixed boundary conditions were estimated using a lateral force microscope (LFM). We find that the tension in the fiber caused during fabrication process scales with fiber diameter and it dominates fiber stiffness. Our studies demonstrate isotropic arrangement of polymer chains in the fibers and anisotropic arrangement in the necking region for fibers undergone deformation. Finally, this study demonstrates development of force sensors capable of measuring single cell forces, which scale with the fiber structural stiffness. The ability to measure cell forces during cell division, migration and apoptosis provides new insights in cell mechanobiology.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Engineering Mechanics

Department dc:contributor.department

Engineering Science and Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2015

Author dc:creator

• Wang, Ji

Chair dc:contributor.committeechair

• Nain, Amrinder

Committee members dc:contributor.committeemember

• Riffle, Judy S.
• Kapania, Rakesh K.
• De Vita, Raffaella
• Moore, Robert Bowen

• STEP
• isodiametric design space
• porous tubes
• single nanofiber mechanical properties
• hierarchical nanofiber assemblies
• cell force measurement

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:4757

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/72958