Feasibility of Predicting Static Dielectric Constants of Polymer Materials: A Density Functional Theory Method.

Zheng Tang,Lei Tian,Huichao Liu,Mingliang Wang,Jian Xu,Chaofan Chang,Caizhen Zhu,Feng Bao

doi:10.3390/polym13020284

Abstract

The rapid development of electronic devices with high integration levels, a light weight, and a multifunctional performance has fostered the design of novel polymer materials with low dielectric constants, which is crucial for the electronic packaging and encapsulation of these electronic components. Theoretical studies are more efficient and cost-effective for screening potential polymer materials with low dielectric constants than experimental investigations. In this study, we used a molecular density functional theory (DFT) approach combined with the B3LYP functional at the 6-31+G(d, p) basis set to validate the feasibility of predicting static dielectric constants of the polymer materials. First, we assessed the influence of the basis sets on the polarizability. Furthermore, the changes of polarizability, polarizability per monomer unit, and differences in polarizability between the consecutive polymer chains as a function of the number of monomers were summarized and discussed. We outlined a similar behavior for the volume of the polymers as well. Finally, we simulated dielectric constants of three typical polymer materials, polyethylene (PE), polytetrafluoroethylene (PTFE), and polystyrene (PS), by combining with the Clausius–Mossotti equation. The simulated results showed excellent agreement with experimental data from the literature, suggesting that this theoretical DFT method has great potential for the molecular design and development of novel polymer materials with low dielectric constants.

Highlights

Nowadays, modern electronic devices and products are developing in the direction of lightness, thinness, high performance, and multifunctionality, following the demands of the growing electronic industry
The Clausius–Mossotti equation [1] can be applied for modeling the dielectric constants of polymer materials if we assume that the polymer materials are composed of identical, nonpolar polymer chains and that chain–chain interactions are negligible
We investigated the feasibility of a molecular density functional theory (DFT) approach combined with the B3LYP functional to predict the dielectric constant of polymer materials

Summary

Introduction

Modern electronic devices and products are developing in the direction of lightness, thinness, high performance, and multifunctionality, following the demands of the growing electronic industry. Weak polar or nonpolar polymer materials are desirable for achieving a low dielectric constant. For the weak polar or nonpolar polymer materials, the relationship between the dielectric constant and the external electric field can be quantitatively expressed by the Clausius–Mossotti equation [1,2]. We show that the dielectric constant depends on the polarizability and volume of the polymer material, implying that the known values of the polarizability and volume of the polymer material can be used to predict its dielectric constant

Methods

Results

Conclusion