title: Surface characterizations of spin-coated films of ethylcellulose and hydroxypropyl methylcellulose blends.
abstract: Films of pure ethylcellulose (EC) and hydroxypropyl methylcellulose (HPMC) polymers and EC/HPMC blends were prepared from solutions by spin coating where isopropyl alcohol (IPA), water, and IPA/water cosolvent were used as solvents. Surface structures of the films were investigated using optical microscopy, atomic force microscopy (AFM), and Raman mapping and spectroscopy. For the films prepared from EC/HPMC blend solutions using the IPA/water cosolvent, different domain structures such as islands or pits and phase separation between EC and HPMC were observed by optical microscopy and AFM. The nature of the polymer components on the surface of the films was identified by Raman mapping and spectroscopy. Experimental results also indicated that polymer composition, solvent, and temperature during spin coating had significant impacts on surface structures of the films.
authors.affiliation: Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, USA.
authors.forename: Yit-Yian
authors.initials: YY
authors.lastname: Lua
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Cao
authors.forename: Brian R
authors.initials: BR
authors.lastname: Rohrs
authors.forename: D Scott
authors.initials: DS
authors.lastname: Aldrich
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D065347:Hypromellose Derivatives; D008567:Membranes, Artificial; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D018625:Microscopy, Atomic Force; D018715:Microscopy, Video; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D012997:Solvents; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013696:Temperature
chemical_list: D008567:Membranes, Artificial; D011108:Polymers; D012997:Solvents; D065347:Hypromellose Derivatives; C013517:ethyl cellulose; D002482:Cellulose; D008747:Methylcellulose