CONFOCAL SCANNING LASER MICROSCOPY OF POLYMER-COATINGS

A new nondestructive technique, confocal scanning laser microscopy (CS LM), is described that is used to characterize the topography and morp hology of polymer coatings. The topography of the coating can be deter mined even when the coating is completely opaque. When the coating is not completely opaque, CSLM has the distinct advantage of also being a ble to distinguish between the coating surface and the substrate, thus enabling coating thickness to be determined over a wide range of area s. In this study CSLM was successfully applied to poly(2-vinylpyridine ) coatings formed on mild steel substrates by in situ electropolymeriz ation. Satisfactory morphological details were obtained for areas rang ing from 200 X 200 mu m to 4 X 4 mm. Quantitative measurements of the coating thickness and the surface roughness distribution were also car ried out. Although several other nondestructive techniques for coating morphological analyses are available, CSLM has unique advantages in b eing able to provide simultaneous qualitative and quantitative informa tion on coating surfaces as well as measurements over a wide range of surface areas. A comparison of CSLM with other popularly used methods is provided and the characteristics and limitations of the various tec hniques are discussed. (C) 1998 John Wiley & Sons, Inc.