Nguyen, Hang
(2020)
MOLECULAR DYNAMICAL SIMULATION OF METAL-CROSSLINKED HYDROGELS.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
This is the latest version of this item.
Abstract
We develop a computational model to study the compaction, network topology and elastic response of hydrogel as a function of crosslink density. Our simulations start with a covalently bonded polymer network, to which we introduce additional crosslinks by binding metal cations to reactive groups distributed along the polymer chains. We find that these crosslinks increase the compaction of the polymer network in two ways: (i) by crosslinking neighboring groups on the same polymer chain and thereby shortening the effective length of polymer chains, and (ii) by linking together two or more distinct polymer chains. These two effects combine to overall hydrogel contraction and stiffening. Our results show that the elastic modulus of the hydrogel increases significantly due to the additional crosslinks, in agreement with recent experimental observations. With the help of computer simulations, we find the relations between parameters of our model and chemical characteristics of the hydrogel such as the modulus, the compaction of hydrogel, or the average number of reactive groups bound to a single crosslinker. We analyze geometric and topological characteristics of the hydrogel, such as the time evolution of distance between groups in the hydrogel, or the proportion of crosslinks that are retained, broken or newly formed during the course of simulations. These characteristics help us better understand the internal structure of the hydrogel and explain experimental observations such as the compaction of the hydrogel when metal crosslinkers are introduced. Despite its simplicity, the model qualitatively captures the important chemical properties of the crosslinkers.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
16 January 2020 |
| Date Type: |
Publication |
| Defense Date: |
10 October 2016 |
| Approval Date: |
16 January 2020 |
| Submission Date: |
1 December 2019 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
106 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Mathematics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
molecular dynamics, simulation, hydrogel, ion, crosslink |
| Date Deposited: |
16 Jan 2020 19:19 |
| Last Modified: |
16 Jan 2020 19:19 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/37971 |
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MOLECULAR DYNAMICAL SIMULATION OF METAL-CROSSLINKED HYDROGELS. (deposited 16 Jan 2020 19:19)
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