Direct measurement of intermolecular forces between a polymer layer and mica

We report here the first direct measurement of intermolecular forces between a polymer layer and a solid surface. When solid surfaces bearing adsorbed polymer approach one another, interactions develop that may be categorized as polymer–polymer and polymer–solid (and a negligible contribution of solid–solid interactions at the large solid–solid separations imposed by adsorbed polymer). Direct measurements of the forces between polymer layers adsorbed on mica have been made recently with apparatus of the type developed by Israelachvili. Attractive forces are attributed to a combination of osmotic (polymer–polymer) and bridging (polymer–solid) interactions. Bridging occurs if macromolecules adsorbed one one surface can reach a second surface. In the work presented here, poly(α‐methylstyrene) (PαMS) adsorbed on one mica sheet was brought into contact in cyclohexane with a bare mica sheet. Adhesion was measured as a function of separation and contact time and found to be more than 20 times greater than between two polymer–coated surfaces under otherwise identical conditions. This direct measurement of molecular forces between dissimilar surfaces enables estimation of the PαMS segmental sticking energy on mica in cyclohexane as (1)/(3) kT.

[1]  P. Pincus,et al.  Interactions between surfaces with adsorbed polymers: poor solvent. 2. Calculations and comparison with experiment , 1986 .

[2]  S. Granick,et al.  Forces between surfaces of block copolymers adsorbed on mica , 1986 .

[3]  G. J. Fleer,et al.  Interaction between two adsorbed polymer layers , 1985 .

[4]  J. Klein,et al.  Interactions between mica surfaces in a polystyrene—cyclopentane solution near the θ-temperature , 1985 .

[5]  P. Luckham,et al.  Forces between two adsorbed poly(ethylene oxide) layers in a good aqueous solvent in the range 0-150 nm , 1984 .

[6]  P. Luckham,et al.  Long-range attractive forces between two mica surfaces in an aqueous polymer solution , 1984, Nature.

[7]  J. Israelachvili,et al.  Forces between two layers of adsorbed polystyrene immersed in cyclohexane below and above the θ temperature , 1984 .

[8]  J. Klein.  Forces between mica surfaces bearing adsorbed macromolecules in liquid media , 1983 .

[9]  Jacob Klein,et al.  Forces between mica surfaces bearing layers of adsorbed polystyrene in cyclohexane , 1980, Nature.

[10]  J. Israelachvili,et al.  Measurement of forces between two mica surfaces in aqueous electrolyte solutions in the range 0–100 nm , 1978 .

[11]  J. Israelachvili,et al.  Direct measurement of long range forces between two mica surfaces in aqueous KNO3 solutions , 1976, Nature.

[12]  J. Cowie,et al.  Phase equilibria in quasi-binary poly(α-methylstyrene) solutions , 1975 .

[13]  Jacob N. Israelachvili,et al.  Thin film studies using multiple-beam interferometry , 1973 .

[14]  B. Derjaguin,et al.  Untersuchungen über die Reibung und Adhäsion, IV , 1934 .