The invention provides a polishing pad substrate comprising a copolymer, wherein the copolymer has at least one hydrophilic repeat unit and at least one hydrophobic repeat unit. The invention also provides a polishing pad substrate comprising a polymer, wherein the polymer is a modified polymer having at least one hydrophilic unit and at least one hydrophobic unit attached to the polymer chain. The invention further provides a method of polishing a workpiece comprising (i) providing a workpiece to be polished, (ii) contacting the workpiece with a chemical-mechanical polishing system comprising the polishing pad substrate of the invention, and (iii) abrading at least a portion of the surface of the workpiece with the polishing system to polish the workpiece.