What is claimed is: 1. A method of measuring the adhesive strength of a polymer interface which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) applying a polymer to at least one of the individual lens elements of the lens array or the substrate; d) contacting the individual lens elements of the lens array and the substrate in a controlled manner; e) separating the individual lens elements of the lens array and the substrate in a controlled manner; f) monitoring changes in contact area of the individual lens elements during at least one of steps d) or e); and g) calculating the adhesive strength of the polymer at the contact area, wherein the step c) of applying the polymer comprises varying at least one of a thickness and a composition of the polymer across the one of the individual lens elements of the lens array or the substrate. 2. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein varying the composition of the polymer comprises varying an amount of at least one component of the polymer. 3. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein the polymer is applied to the individual lens elements of the lens array. 4. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein changes in contact area of the individual lens elements are optically monitored. 5. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein at least one of the lens array and the substrate is non-planar. 6. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein the step contacting the lens array and substrate in a controlled manner comprises moving the lens array with respect to the substrate. 7. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein the individual lens elements have convex surfaces. 8. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein the individual lens elements have a shape selected from the group consisting semi-spherical, frusto-conical, cylindrical, trapezoidal and frusto-pyramidal shapes. 9. A method of measuring the adhesive strength of a polymer interface according to claim 1, wherein at least one of the lens array and the substrate is made from a metal or ceramic and does not have the polymer applied thereto. 10. A method of measuring the adhesive strength of a polymer interface which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) applying a polymer to at least one of the individual lens elements of the lens array or the substrate; d) providing at least one of a physical gradient, an environmental gradient, and a material gradient across an interface between the lens array and substrate; e) contacting the individual lens elements of the lens array and the substrate in a controlled manner; f) separating the individual lens elements of the lens array and the substrate in a controlled manner; g) monitoring changes in contact area of the individual lens elements during at least one of steps d) or e); and h) calculating the adhesive strength of the polymer at the contact area. 11. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) contacting the individual lens elements of the lens array with the substrate in a controlled manner while providing a parameter gradient there between, said parameter gradient comprising at least one of a physical parameter, an environmental parameter and a material parameter; and d) calculating the adhesive strength of the polymer at the contact areas, wherein the step of providing a parameter gradient between the lens array and the substrate comprises applying a polymer material to at least one of each of the individual lens elements of the lens array or to the substrate. 12. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library according to claim 11, wherein the step of providing a parameter gradient between the lens array and the substrate comprises applying a pattern of different polymer material to one of the individual lens elements of the lens away or the substrate. 13. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) contacting the individual lens elements of the lens array with the substrate in a controlled manner while providing a parameter gradient there between, said parameter gradient comprising at least one of a physical parameter, an environmental parameter and a material parameter; and d) calculating the adhesive strength of the polymer at the contact areas, wherein the step of providing a parameter gradient between the lens array and the substrate comprises providing a gradient of strain between the lens array and the substrate. 14. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) contacting the individual lens elements of the lens array with the substrate in a controlled manner while providing a parameter gradient there between, said parameter gradient comprising at least one of a physical parameter, an environmental parameter and a material parameter; and d) calculating the adhesive strength of the polymer the contact areas, wherein the step of providing a parameter gradient between the lens array and the substrate comprises controlling an environmental condition at an interface between the lens array and the substrate. 15. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) contacting the individual lens elements of the lens array with the substrate in a controlled manner while providing a parameter gradient there between, said parameter gradient comprising at least one of a physical parameter, an environmental parameter and a material parameter; and d) calculating the adhesive strength of the polymer at the contact areas, wherein changes in contact area of the individual lens elements are optically monitored. 16. A method for measuring the adhesive strength of polymer material interfaces that are arranged in a combinatorial library which comprises the steps of: a) providing a lens array having a plurality of individual lens elements on a surface thereof; b) providing a substrate; c) contacting the individual lens elements of the lens array with the substrate in a controlled manner while providing a parameter gradient there between, said parameter gradient comprising at least one of a physical parameter, an environmental parameter and a material parameter; and d) calculating the adhesive strength of the polymer at the contact areas, wherein at least one of the lens array and the substrate is non-planar. 17. A test device for measuring the adhesive strength of polymer materials that are arranged in a combinatorial library which comprises: a substrate having opposed surfaces; and a polymer material applied to one of the opposed surfaces of the substrate so that the composition of the polymer material varies along at least one direction across the one opposed surface of the substrate, wherein the one opposed surface of the substrate is provided with an array of lens elements.