Molecular Dynamic Simulation of Polysiloxane

Polymer Derived Ceramics are a promising class of Materials that allow for higher levels of tunability and shaping that traditional sintering methods do not allow for. Polysiloxanes are commonly used as a precursor for these types of material because of their highly tunable microstructures by adjusting the side groups on the initial polymer. These Polymers are generally cross linked and pyrolyzed in inert atmospheres to form the final polymer. The microstructures of Polymer Derived Ceramics is complex and hard to observe due to the size of each microstructure region and the proximity in the periodic table that the elements present have. The process of forming phases such as Graphitic Carbon, Amorphous Carbon, Silicon Carbide. Silicon Oxide, and SiliconOxycarbide are not well understood. Simulation provides a route to understanding the phenomenon behind these phase formations. Specifically, Molecular dynamics simulation paired with the Reaxff forcefield provides a framework to simulate the complex processes involved in pyrolysis such as chemical reactions and a combination of thermodynamic and kinetic interactions. This Thesis examines firstly the size effect that a system can have on phase separation and the change in composition. Showing that size plays a major role in how the system develops and limits the occurrence of specific reactions. Secondly, this thesis shows that using polymer precursors with different initial polymer components leads to vastly different microstructures and yield. This provides insights into how the transition from polymer to ceramic takes place on a molecular level.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Materials Science and Engineering

Department dc:contributor.department

Materials Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2023

Author dc:creator

• Chaney, Harrison Matthew

Chair dc:contributor.committeechair

• Lu, Peizhen

Committee members dc:contributor.committeemember

• Bai, Xianming
• Deshmukh, Sanket A.

• Polymer Derived Ceramics
• Molecular Dynamic Simulation
• Reaxff

Statement dc:rights

• Creative Commons Attribution 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by/4.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:36678

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/114459