title: In SituSelf Assembly of Nanocomposites: Competition of Chaotic Advection and Interfacial Effects as Observed by X-Ray Diffreaction.
abstract: The effects of chaotic advection on thein situassembly of a hierarchal nanocomposite of Poly Amide 6, (nylon 6 or PA6) and platelet shape nanoparticles (NPs) were studied. The assemblies were formed by chaotic advection, where melts of pristine PA6 and a mixture of PA6 with NPs were segregated into discrete layers and extruded into film in a continuous process. The process assembles the nanocomposite into alternating pristine-polymer and oriented NP/polymer layers. The structure of these hierarchal assemblies was probed by X-rays as a processing parameter, N, was varied. This parameter provides a measure of the extent ofin situstructuring by chaotic advection. We found that all assemblies are semi-crystalline at room temperature. Increasing N impacts the ratio of α to γ crystalline forms. The effects of the chaotic advection vary with the concentration of the NPs. For nanocomposites with lower NP concentrations the amount of the γ crystalline form increased with N. However, at higher NP concentrations, interfacial effects of the NP play a significant role in determining the structure, where the NPs oriented along the melt flow direction and the polymer chains oriented perpendicular to the NP surfaces.
authors.affiliation: Department of Chemistry, Clemson University, Clemson, SC 29634-0973, USA. dratnaw@clemson.edu.
authors.forename: Dilru R
authors.initials: DR
authors.lastname: Ratnaweera
authors.affiliation: Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921, USA. cmahesh@clemson.edu.
authors.forename: Chaitra
authors.initials: C
authors.lastname: Mahesha
authors.affiliation: Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921, USA. zdavid@clemson.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Zumbrunnen
authors.affiliation: Department of Chemistry, Clemson University, Clemson, SC 29634-0973, USA. dperahi@clemson.edu.
authors.forename: Dvora
authors.initials: D
authors.lastname: Perahia
keywords: X-ray diffraction; assembly; chaotic advection; nanocomposites; nylon; smart blending