Atomic force microscopy of single polymer chains on a substrate at temperatures above the bulk glass transition temperatures. (2nd April 2019)

• Record Type: Journal Article
• Authors: Fujita, Ryo; Furudate, Kenshiro; Kumaki, Jiro
• Is Part Of: Polymer. Volume 168(2019)
• Page Start: 21
• Page End: 28
• Publication Date: 2019-04-02
• Subjects: Isolated chain -- Atomic force microscopy -- High temperature -- Movement -- Glass transition temperature; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2019.02.014
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Polymer chains adsorbed on substrates have been observed by atomic force microscopy (AFM); however, observations at high temperatures are not well studied. We observed isolated chains of isotactic and atactic poly(methyl methacrylate) (it-, and at-PMMA) and poly(2-vinyl pyridine) (P2VP) on mica up to 200 °C, which is above their bulk glass transition temperature ( T g ), and found that isolated chains could be observed even at temperatures much higher than the bulk T g . The thicknesses of the chains were constant up to 200 °C, but the radius of gyration ( R g ) of the chains started to decrease at 100 °C for it- and at-PMMA and at 150 °C for P2VP. In situ AFM observations indicated that the chains started moving at these temperatures, which were approximately 40, 0, and 55° above their bulk T g . The restricted movements of the isolated chains should provide useful information to understand the surface phenomena of polymers at the molecular level. Graphical abstract: Image 1 Highlights: Isolated chains of it-. at-PMMA and P2VP on mica were observed by AFM in situ at temperatures up to 200 °C. These chains started moving at temperatures of approximately 40, 0, and 55° above their bulk T g, respectively. The movements of the isolated chains provide useful information for understanding the surface phenomena of the polymers.