METHOD OF CHANGING THE WETTABLILITY OF PLASTIC SURFACES BY SOLVENT-INDUCED PRECIPITATION OR SOLVENT-INDUCED CRYSTALLIZATION

摘要

A method for making an article comprises the following steps: providing a polyamide substrate; contacting a selected surface region of the polyamide substrate with a swelling agent having a high solubility limit for the polyamide substrate, whereby a surface part of the polyamide substrate is swollen and a part underneath the surface is non-swollen; contacting the swollen polyamide substrate with a coagulating agent having a low solubility limit for the polyamide and being miscible with the swelling agent, whereby the swollen part of the polyamide substrate is first precipitated and then crystallized back onto the non-swollen part. With the method, an article having a structured hydrophilic or superhydrophilic polyamide surface is obtained.