A coated microcapillary column for high performance electrophoresis is disclosed. A preferred microcapillary includes a fused silica capillary column, the inner surface of the column having an interconnected polymeric coating of a polyvinyl alcohol (PVA) based polymer covalently attached to the column wall by Si--O--Si bonds. The resulting coated microcapillary column has good hydrolytic and pH stability and minimizes electroosmotic flow and interactions between sample components and the capillary wall. Also disclosed are a method of forming a polymeric coating layer for any surface by polymerizing the appropriate organic compounds in an organic solvent and a method of forming a column with a hydrophilic polymeric coating by directly converting an attached hydrophobic polymeric coating material to a hydrophilic polymeric coating material.