Characterization and Control of an Electrospinning Process

Optical observations of jets provide information useful for control of electrospinning of polymer solutions. Combinations of videography, stereography, and methods for illumination of the multiple coils of an electrospinning jet path, that depend on bright glints of reflected light from the jet, recorded quantitative information about the location and vector velocity of selected segments of the jet. New bending coils were observed to form at rates of 200-1560 turns per second. This bending frequency decreased as the capillary number of the solutions increased. The motion of mergence of coils of a jet was discovered and characterized. This characterization, combined with bending frequency, provides information for control of parameters in fiber collection in nonwoven products. The polarization of light, in glints reflected at Brewster's angle, allows measurement of the index of refraction of the fluid jet, in flight. Birefringence of a coiled charged jet was observed for the first time, providing information about the extension and order of molecular chains in a jet. Asymmetric illumination of an electrospinning jet made both the handedness and changes in handedness of the electrical bending coils apparent to visual observation and in 2-dimensional images. Other reliable methods for handedness characterization of a coiled jet were also established and introduced. Evidence was found, in the form of polarized ribbon-like glint traces, for the occurrence of undulations on the surface of some jets. New strategies were established for external initiation of multiple electrospinning jets at lower voltages than usual without the formation of a Taylor cone.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Polymer Science

Grantor dc:publisher

University of Akron

Year dc:date

2013

Author dc:creator

• Liu, Kaiyi

Contributors dc:contributor

• Reneker, Darrell H.
• Wang, Shi-Qing

• Materials Science
• Nanotechnology
• Polymers
• electrospinning
• polymer liquid jet
• illumination
• high speed video
• stereo pictures
• bending frequency
• handedness
• coil mergence
• Brewster's angle
• polarized glint
• glint trace
• birefringence
• multiple jet
• Taylor cone
• external initiation
• jet motion

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=akron1355239985

OAI identifier oai:identifier

oai:etd.ohiolink.edu:akron1355239985