Tabrizi, Mohsen
(2022)
Three-dimensional Blueprinting of Molecular Patterns in Liquid Crystalline Polymers.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The ability to pattern material response, voxel-by-voxel, to direct actuation and manipulation in macroscopic structures can enable devices that utilize ambient stimuli to produce functional responses at length-scales ranging from the micro- to the macroscopic. Fabricating stimuli-responsive liquid crystalline (LC) polymeric materials, where the molecular director is indexably defined in three-dimensional freeforms can be a key enabler. Here, we exploited the combination of anisotropic magnetic susceptibility of the LC monomers in a reorientable magnetic field and spatially-selective photopolymerization using a digital micromirror device to independently define molecular orientation in light and/or heat responsive multi-material elements, which are additively incorporated into three-dimensional freeforms. This enables structural complexity across length scales in non-trivial geometries which are responsive to either heat or light. In this work, the mechanism of magnetically controlling the molecular orientation of various LC polymeric materials is studied. Based on the results, a new liquid crystalline elastomer (LCE) that can be aligned by low-intensity magnetic field was developed. The proposed platform and new LCE material are further exploited by the development of a battery-free, remotely controlled, bioinspired microflier with potential applications in environmental monitoring. This study can provide the opportunity to expand the applications of molecularly ordered materials to soft robotics and micromechanical devices that are driven by unconventional stimuli. The current and ongoing research works to expand the implementations of this work vision including sub-voxel control over molecular order, endowing multifunctionality, scaling the artificial muscle down to nanoscale, and exploitation of self-sensing and self-regulation are discussed briefly in the end.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
10 June 2022 |
| Date Type: |
Publication |
| Defense Date: |
16 March 2022 |
| Approval Date: |
10 June 2022 |
| Submission Date: |
10 April 2022 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
109 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Industrial Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
smart materials, liquid crystal polymers, additive manufacturing, 4D printing, soft robotics |
| Date Deposited: |
10 Jun 2023 05:00 |
| Last Modified: |
10 Jun 2023 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/42568 |
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