One aspect of the present invention provides instruments for measuring mechanical properties of a combinatorial library of materials. The instruments include at least one capacitor to which a member of a library of material samples is removably secured for testing; at least one voltage source for delivering one or more forces to each library member; and at least one sensing device for monitoring the response each library member to the one or more forces. Another aspect of the present invention provides methods of screening a combinatorial library of materials where the method monitors the responses of a plurality of samples on a substrate to a force induced by a capacitor.