Accession Number : ADA309073

Title :   Tailored Polymer/Nonpolymer Interfaces for Controlled Adhesion.

Descriptive Note : Final rept. 15 Aug 91-14 Aug 95,

Corporate Author : CORNELL UNIV ITHACA NY

Personal Author(s) : Kramer, Edward J.

PDF Url : ADA309073

Report Date : 14 OCT 1995

Pagination or Media Count : 28

Abstract : A method of tuning and analyzing the fracture properties of polymer/nonpolymer interfaces by the controlled addition to the interface of deuterium labelled block copolymers has been developed. Forward recoil spectrometry (FRES) was used to measure the interface excess of the labelled copolymers and this technique along with Rutherford backscattering spectrometry was used to determine the locus of fracture along the interface, thus revealing molecular details of the fracture process. These results were correlated with the fracture toughness Gc measured using an asymmetric cantilever beam specimen developed to guide the crack along the interface of interest. A model system consisting of an interface between glass and polystyrene with block copolymers of deuterated polystyrene (d-PS) and poly(2vinylpyridine) (PVP) was used. Effective methods for manipulating the Gc were discovered, even at a modest areal chain density of the block copolymer, by changing the lengths of the d-PS and PVP blocks thus avoiding pull-out of the dPS block from the PS and pull-off of the PVP from the glass. Forming a self-assembled methyl-terminated monolayer on the glass led to very low Gc by preventing hydrogen bonding between the PVP and silanol groups on the glass.

Descriptors :   *CONTROL, *INTERFACES, *POLYMERS, *ADHESION, *FRACTURE(MECHANICS), DENSITY, HYDROGEN BONDS, MODELS, BLOCK COPOLYMERS, POLYSTYRENE, COPOLYMERS, SPECTROMETRY, TOUGHNESS, BACKSCATTERING, CHAINS, TUNING, RECOIL, PYRIDINES, LABELED SUBSTANCES, LOCUS, DEUTERIUM COMPOUNDS.

Subject Categories : Polymer Chemistry
      Organic Chemistry
      Physical Chemistry
      Adhesives, Seals and Binders
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE