title: Interphase Induced Dynamic Self-Stiffening in Graphene-Based Polydimethylsiloxane Nanocomposites.
abstract: The ability to rearrange microstructures and self-stiffen in response to dynamic external mechanical stimuli is critical for biological tissues to adapt to the environment. While for most synthetic materials, subjecting to repeated mechanical stress lower than their yield point would lead to structural failure. Here, it is reported that the graphene-based polydimethylsiloxane (PDMS) nanocomposite, a chemically and physically cross-linked system, exhibits an increase in the storage modulus under low-frequency, low-amplitude dynamic compressive loading. Cross-linking density statistics and molecular dynamics calculations show that the dynamic self-stiffening could be attributed to the increase in physical cross-linking density, resulted from the re-alignment and re-orientation of polymer chains along the surface of nano-fillers that constitute an interphase. Consequently, the interfacial interaction between PDMS-nano-fillers and the mobility of polymer chain, which depend on the degree of chemical cross-linking and temperature, are important factors defining the observed performance of self-stiffening. The understanding of the dynamic self-stiffening mechanism lays the ground for the future development of adaptive structural materials and bio-compatible, load-bearing materials for tissue engineering applications.
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Linlin
authors.initials: L
authors.lastname: Cao
authors.affiliation: Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China.
authors.forename: Yanlei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Pei
authors.initials: P
authors.lastname: Dong
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Soumya
authors.initials: S
authors.lastname: Vinod
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Jaime Taha
authors.initials: JT
authors.lastname: Tijerina
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.affiliation: Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Lou
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon; D006108:Graphite
keywords: dynamic self-stiffening; graphene-based nanocomposites; interfacial interaction; interphase evolution