Micro-and macromechanics of single crystal and polygrannular lamellar block copolymers

Block copolymers (BCPs) are a relatively new class of thermoplastic elastomers. Their macromolecular chain consists of covalently bonded repeating blocks of thermoplastic and elastomeric molecular chains. When given the thermodynamic freedom, the chain constituents phase separate into domains of various morphologies with sizes that can range between ten to hundreds of nanometers. BCPs are in essence nanocomposites with chemically bonded interfaces. As such, their mechanical behavior is consistent both with that of elastomers, and of thermoplastics. Due to this unique behavior, BCPs are among the most popular polymeric materials with diverse commercial applications that cover a number of industries. Furthermore, BCPs are emerging as instrumental for the future of nanotechnology as an increasing number of new techniques and applications seek to utilize their nanostructural features. BCPs, whether as polycrystalline configurations or as "highly" oriented single-crystals, attract an accumulating number of applications, and the increasing demand for efficient material design and product development extends over a range of length scales. Hence, there exists a need for continuum models that will predict both the oriented as well as the polycrystalline response of block-polymer materials to generic loading conditions. This thesis presents a general micromechanical framework for the derivation of large-strain continuum constitutive models for hyperelastic materials with layered micro- or macro-structures. The framework was implemented for the case of oriented (single-crystal) lamellar BCPs with Neo-Hookean phase behavior, and an analytical continuum model was derived for their large-strain hyperelastic response.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Tzianetopoulou, Theodora, 1974-

Advisor dc:contributor.advisor

• Mary C. Boyce.

• Mechanical 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/1721.1/42293

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42293