figshare
Browse

Enthalpy Relaxation and Morphology Evolution in Polystyrene‑b‑poly(methyl methacrylate) Diblock Copolymer

Posted on 2018-09-14 - 14:49
Desirable patterns formed by microphase separation in block copolymers make these materials attractive for miniaturization of functional devices in which formation of nanostructures is highly demanded. The microphase separation forms microdomains under three-dimensional confinement for each component and thus substantially changes physical properties such as structural relaxation of the polymer blocks. In this article, we report enthalpy relaxation and morphology evolution in polystyrene-b-poly­(methyl methacrylate) (PS-b-PMMA) during isothermal physical aging, measured by calorimetry and atomic force microscopy (AFM). Under nanoconfinement formed by microphase separation, the PS blocks have higher relaxation rate and amount of relaxed enthalpy compared with the corresponding homo-PS, while the PMMA blocks have lower relaxation rate and relaxed enthalpy than the homo-PMMA. The in situ morphology evolution shows that the characteristic distribution profiles of the AFM phase angle become lower and wider with increasing aging time for both the blocks, and the average distance between the central phase angles of the two blocks increase during aging. As large AFM phase angle of PMMA representing higher modulus, it demonstrates that the PS blocks under hard confinement exhibit greater enthalpy change with enhanced relaxation rate from the bulk. In contrast, PMMA blocks under soft confinement show the opposite trend.

CITE THIS COLLECTION

DataCite
3 Biotech
3D Printing in Medicine
3D Research
3D-Printed Materials and Systems
4OR
AAPG Bulletin
AAPS Open
AAPS PharmSciTech
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg
ABI Technik (German)
Academic Medicine
Academic Pediatrics
Academic Psychiatry
Academic Questions
Academy of Management Discoveries
Academy of Management Journal
Academy of Management Learning and Education
Academy of Management Perspectives
Academy of Management Proceedings
Academy of Management Review
or
Select your citation style and then place your mouse over the citation text to select it.

SHARE

email
need help?