MODIFICATION, RECONSTRUCTION, AND REORGANIZATION OF SULFONATED POLYETHYLENE SURFACES

Sulfonated polyethylene is a readily prepared hydrophilic surface-modified version of polyethylene. The initially prepared sulfonated surface undergoes acid-base reactions to incorporate metal salts, amines, and basic dyes, but these reactions are slower than similar reactions with soluble alkylsulfonic acids. Reconstruction and reorganization of sulfonated polyethylene surfaces containing unmodified sulfonic acid groups carried out both in vacuum and in various solvents leads to changes in surface wettability. Initially a more hydrophilic surface was produced. Prolonged annealing times (>3 days at 70 degrees C) or temperatures above 70 degrees C eventually produce a more hydrophobic surface. At 70 degrees C, these changes are reversible. Qualitatively similar reorganization occurs for ammonium sulfonate salt surfaces. However, simple sulfonate surfaces containing alkali metal cations retain their hydrophilicity under mild heating (12 h at 70 degrees C).