Nanostructured electrospun fibers : from superhydrophobicity to block copolymer self-assembly

Electrospinning has emerged in recent years as a relatively easy, efficient and robust method to make ultrafine continuous fibers with diameter on the order of -100 nm from a variety of materials. As a result, numerous applications for electrospun fibers have already been demonstrated including the commercialized ones in the areas of filtration and tissue engineering. However, in most cases, the nanofibers are homogeneous; the development of external and internal nanostructures could significantly expand the applications of these fibers. The goal of this dissertation is therefore to develop controllable nanostructures for electrospun fibers with an emphasis on the understanding of structure formation and explore their unique applications. Specifically, this dissertation can be divided into two areas. The first part is related to superhydrophobic or "self-cleaning" surfaces. This has been a hot research area due to the wide applications of such materials. Electrospun fibers were first discovered in this dissertation to have sufficient surface roughness for superhydrophobic effect. In contrast to many conventional superhydrophobic surfaces, those composed of electrospun fibers are flexible, breathable and free-standing. It has been demonstrated that superhydrophobic fabrics can be made by either electrospinning a hydrophobic material or applying post-treatment to electrospun mats (e.g. through initiated chemical vapor deposition). Based on an understanding of the role of fibrous structure to create a surface of suitable topology, different strategies have been invented to enhance the superhydrophobic property and its robustness by carefully designing the external nanostructures of individual fibers using various methods such as layer-by-layer assembly. Other functionalities such as transparency and fluorescence were successfully incorporated into superhydrophobic surfaces. In particular, superhydrophobic fibrous membranes with structural colors as those displayed by some beautiful butterfly wings were produced. Besides making superhydrophobic materials from the externally nanostructured fibers, internally nanostructured electrospun fibers were also developed through the microphase separation of cylindrically confined block copolymer systems.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Ma, Minglin

Advisor dc:contributor.advisor

• Gregory C. Rutledge.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/45928

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/45928