Using Simulations and Data to Understand the Effect of the Interphase on Polymer Nanocomposite Properties

Polymer nanocomposites (PNCs) are advanced materials that take advantage of both the properties of polymer matrix and nano-scale reinforcement. The interphase, the region between the matrix and the nano-filler, plays a critical role in determining and predicting the overall properties of PNCs. Here, we showcase the potential of the materials data infrastructure, such as the NanoMine database, which is a new materials data resource that collects annotated experimental data on PNCs, to assist fundamental materials understanding and therefore rational materials design. This specific case study is built around studying the relationship between the change in glass transition temperature () and the interfacial surface energy of the nanofillers and the polymer matrix in PNCs. We sifted through data from over 2000 experimental samples curated into NanoMine, used descriptors from the data in additional heuristic modeling tools to augment the dataset, and built a multilinear regression metamodel to predict PNC . Further analysis points to the importance of additional analysis of parameters from processing methodologies and continuously adding curated datasets to increase sample pool size. Overall, results demonstrate the power of using aggregated materials data to gain insight and predictive capability. The results also indicate the critical role of dispersion and the interphase properties, which are typically unknown. To bridge this gap, Molecular Dynamic simulations are used to assess the local polymer property changes resulting from the combined effect of interfacial polymer interactions with particles and particle-particle proximity. Approaches to scale the local mechanical properties of the interphase obtained from these simulations are discussed in order to use them as input for finite element analysis, to bridge the molecular and continuum length scales. The importance of molecular scale insight to understand and predict key features of the interphase and its impact on nanocomposite design is illustrated.