{"title":"Film Thickness Dependence of Surface and Internal Morphology Evolution in Polymer-Grafted Nanocomposites","authors":"Aria C. Zhang, Kohji Ohno, Russell J. Composto","doi":"10.1021/acs.macromol.4c00854","DOIUrl":null,"url":null,"abstract":"This study investigates the interplay between film thickness and the surface and internal morphologies in polymer nanocomposite (PNC) films. The PNC is 25 wt % poly(methyl methacrylate)-grafted silica nanoparticles (NPs) in poly(styrene-<i>ran</i>-acrylonitrile) annealed in the two-phase region. At greatest confinement (120 nm), NP surface density remains constant, and lateral phase separation is inhibited upon annealing. For thicker films (240–1400 nm), surface density increases with time before approaching ca. 740 NP/μm<sup>2</sup>, consistent with 2D random close packing. Moreover, lateral domain growth exhibits a dimensional crossover as thickness increases from <i>t</i><sup>1/2</sup> to <i>t</i><sup>1/3</sup>, consistent with domain coalescence. Water contact angles decrease upon annealing in agreement with the lateral domain composition. For thickest films (1400–4000 nm), a morphology map summarizes the distinct internal arrangements of NPs: disordered aggregates, continuous vertical pillars, discrete vertical pillars, isolated domains, and random networks. This study of PNC films provides guidance for controlling surface and bulk structure which can lead to improved barrier, mechanical, and transport properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":null,"pages":null},"PeriodicalIF":5.1000,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Macromolecules","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.macromol.4c00854","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
This study investigates the interplay between film thickness and the surface and internal morphologies in polymer nanocomposite (PNC) films. The PNC is 25 wt % poly(methyl methacrylate)-grafted silica nanoparticles (NPs) in poly(styrene-ran-acrylonitrile) annealed in the two-phase region. At greatest confinement (120 nm), NP surface density remains constant, and lateral phase separation is inhibited upon annealing. For thicker films (240–1400 nm), surface density increases with time before approaching ca. 740 NP/μm2, consistent with 2D random close packing. Moreover, lateral domain growth exhibits a dimensional crossover as thickness increases from t1/2 to t1/3, consistent with domain coalescence. Water contact angles decrease upon annealing in agreement with the lateral domain composition. For thickest films (1400–4000 nm), a morphology map summarizes the distinct internal arrangements of NPs: disordered aggregates, continuous vertical pillars, discrete vertical pillars, isolated domains, and random networks. This study of PNC films provides guidance for controlling surface and bulk structure which can lead to improved barrier, mechanical, and transport properties.
期刊介绍:
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.