Interfacial surface generator

A method for making multilayer films having a prescribed distribution of the thicknesses of the layers of one or more materials from one major surface of the film to an opposing surface, comprising the steps of:

• dividing a first composite stream comprised of
• discrete overlapping layers of the one or more materials, of which at least a pair of such layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers,
• into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;
• repositioning at least the two or more branch streams along both of the x- and y-axes as the branch streams flow along the z-axis;
• independently adjusting the flow rates of at least the two or more branches streams to which the pair of discrete overlapping layers and the generally planar layer interface therebetween were distributed;
• recombining the plurality of branch streams in overlapping relationship to form a second composite stream having a greater number of discrete overlapping layers of the one or more materials than the first composite stream in the prescribed distribution;
• symmetrically expanding a transverse dimension of the second composite stream along the x-axis;
• and
• symmetrically contracting the thickness of the second composite stream along the y-axis.

An apparatus for generating interfacial surfaces within a first composite stream comprised of discrete overlapping layers of the one or more materials, of which at least a pair of such layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendicularly away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, said apparatus comprising:

• dividing means for dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;
• a plurality of first conduits for repositioning the branch streams along both the x-axis and the y-axis;
• a plurality of second conduits in fluid communication with the first conduits, with each second conduit having a progressively greater transverse dimension along the x-axis from an inlet opening to an outlet port thereof, the inlet opening being positioned centrally in the apparatus;
• a plurality of third conduits in fluid communication with the second conduits, with each third conduit having a dimension in the y-direction which becomes progressively lesser from an inlet opening to an outlet port thereof;
• means for individually adjusting the dimension in the y-direction of each of the third conduits at a downstream end thereof;
• and
• means for recombining the branch streams from the third conduits to form a second composite stream which comprises a greater number of discrete overlapping layers of the one or more materials than the first composite stream in the prescribed distribution.

An apparatus for generating interfacial surfaces within a first composite stream comprised of discrete overlapping layers of the one or more materials, of which at least a pair of such layers define a generally planar layer interface therebetween which lies generally in an x-z plane of an x-y-z coordinate system, wherein the z-axis is taken as extending in the general direction of flow of the first composite stream, the x-axis extends transversely of the first composite stream and defines a transverse dimension of the layer interface, and the y-axis extends generally perpendiculary away from the planar layer interface in the thickness direction of the pair of discrete overlapping layers, said apparatus comprising:

• dividing means for dividing the first composite stream into a plurality of branch streams along the x-axis, such that the pair of discrete overlapping layers and the generally planar layer interface defined therebetween are distributed among two or more of the branch streams;
• a plurality of first conduits for repositioning the branch streams along both the x-axis and the y-axis;
• means for individually adjusting the dimension in the y-direction of each of the first conduits at a downstream end thereof;
• and
• a conduit wherein the branch streams are recombined and symmetrically expanded and contracted, said conduit defining a tetrahedral cavity through which the recombined branch streams flow, the cavity being formed by the intersection of the sides of the conduit in the form of four isosceles triangles or equilateral triangles.