Insights into the Influence of Solvent Polarity on the Crystallization of Poly(ethylene oxide) Spin-Coated Thin Films via in Situ Grazing Incidence Wide-Angle X-ray Scattering

DOI: 10.1021/acs.macromol.6b00312

Authors: Daniel Toolan (University of Sheffield) , Anna Isakova (Aston University) , Richard Hodgkinson (University of Sheffield) , Nik Reeves-mclaren (University of Sheffield) , Oliver Hammond (University of Bath) , Karen J. Edler (University of Bath) , Wuge Briscoe (University of Bristol) , Tom Arnold (Diamond Light Source) , Tim Gough (University of Bradford) , Paul Topham (Aston University) , Jon Howse (University of Sheffield)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Macromolecules , VOL 49 , PAGES 4579 - 4586

State: Published (Approved)
Published: June 2016
Diamond Proposal Number(s): 9328

Abstract: Controlling polymer thin-film morphology and crystallinity is crucial for a wide range of applications, particularly in thin-film organic electronic devices. In this work, the crystallization behavior of a model polymer, poly(ethylene oxide) (PEO), during spin-coating is studied. PEO films were spun-cast from solvents possessing different polarities (chloroform, THF, and methanol) and probed via in situ grazing incidence wide-angle X-ray scattering. The crystallization behavior was found to follow the solvent polarity order (where chloroform < THF < methanol) rather than the solubility order (where THF > chloroform > methanol). When spun-cast from nonpolar chloroform, crystallization largely followed Avrami kinetics, resulting in the formation of morphologies comprising large spherulites. PEO solutions cast from more polar solvents (THF and methanol) do not form well-defined highly crystalline morphologies and are largely amorphous with the presence of small crystalline regions. The difference in morphological development of PEO spun-cast from polar solvents is attributed to clustering phenomena that inhibit polymer crystallization. This work highlights the importance of considering individual components of polymer solubility, rather than simple total solubility, when designing processing routes for the generation of morphologies with optimum crystallinities or morphologies.

Subject Areas: Chemistry


Instruments: I07-Surface & interface diffraction

Other Facilities: European Synchrotron Radiation Facility