Equilibrium surface composition of diblock copolymers

Journal Article · Sun Jan 14 23:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458106· OSTI ID:7202888

Green, P F; Christensen, T M ^[1]; Russell, T P ^[2]; Jerome, R ^[3]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185-5800 (USA)
2. IBM Research Division, Almaden Research Center, San Jose, California 95120-6099 (USA)
3. Laboratory of Molecular Chemistry and Organic Catalysis, University of Liege, Liege (Belgium)

The surface composition of a series of symmetric diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) was studied using x-ray photoelectron spectroscopy (XPS). Each copolymer was composed of {ital N} segments where {ital N} ranged from 270 to 5200. At large {ital N}, where the system is highly segregated, the surface is composed only of PS, the lower surface energy component. For smaller {ital N}, where the system is in the weak segregation limit, both the PS and PMMA segments coexist at the surface. The surface excess {psi}{sub 1} of PS in the weak segregation limit is well described by {psi}{sub 1}={alpha}{minus}{beta}{ital N}{sup {minus}1/2}, in good agreement with mean field predictions. The constants {alpha} and {beta} depend on the interactions between the unlike segments on the copolymer chain and on the surface energy differences between the components. We also show that the strength of the segmental interactions in the vicinity of the surface are weaker than from those in the bulk.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7202888
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 92:2; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CHAINS
CHEMICAL COMPOSITION
COPOLYMERS
ELECTRON SPECTROSCOPY
ENERGY
ESTERS
FREE ENERGY
INTERACTIONS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHOTOELECTRON SPECTROSCOPY
PHYSICAL PROPERTIES
PLASTICS
PMMA
POLYACRYLATES
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYVINYLS
SPECTROSCOPY
SURFACE ENERGY
SURFACE PROPERTIES
SYNTHESIS
SYNTHETIC MATERIALS
THERMODYNAMIC PROPERTIES