Date of Award

Fall 2014

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Materials Science

First Advisor

Alejandro Strachan

Second Advisor

James M. Caruthers

Committee Chair

Alejandro Strachan

Committee Member 1

James M. Caruthers

Committee Member 2

Marisol Koslowski

Committee Member 3

R. B. Pipes


Polymer matrix composites reinforced with carbon nanotubes (CNTs) have received significant attention due to their potential for exceptional mechanical, electrical, thermal and optical properties. The enhancement of ultimate mechanical properties of CNT reinforced polymer composites is governed not just by the properties of the two phases but by dispersion of the CNTs, interactions in the interfacial region and local molecular changes in polymer due to the vicinity of the CNTs. Strong adhesive interactions between the matrix and CNT leads to good compatibility preventing the aggregation of the reinforcements and results in optimal mechanical response. Even though significant efforts have been devoted to the understanding of fundamental issues regarding the synthesis and properties of these materials, a predictive understanding of the interaction between CNTs and polymer matrices is lacking resulting in sub-optimal properties. ^ We use molecular dynamics simulations to characterize the effective CNT-CNT and CNT-matrix interactions as well as mechanical response of CNT-reinforced composite. We find that the short-range CNT-CNT interaction is governed by the perturbations caused on the polymer local structures by the CNTs. Interestingly, we find that these interactions are not pairwise additive and characterize the many body effects. We also quantify how these short-range perturbations of the polymer structure affect their local mechanical response and that of the composite as a whole. We find the local stiff of the polymer near the CNTs is 30 times higher than that of the bulk. ^ Our study provides key insight and parameters into the basis of interactions in CNT reinforced polymer nanocomposites that could help the design of optimized materials.