A thermoplastic interlayer having an embossed surface pattern wherein the pattern provides relatively uninterrupted channels for de-airing in at least two non-parallel directions, said channels having depth of less than about 20 μm, and width about 30 μm to about 300 μm and spaced between about 0.1 mm and about 1 mm apart, and said surface pattern has roughness parameters such that the area roughness peak height (ARp) is less than 32 μm, and the ratio of the area peak height (ARp) to area roughness (ARt) is between 0.52 and 0.62, and the area kurtosis (AKu) is less than 5, wherein said interlayer is an ionoplastic polymer.