An apparatus and method for screening
combinatorial libraries of materials by measuring the
response of individual library members to mechanical
perturbations is described. The apparatus generally
includes a sample holder for containing the library
members, an array of probes for mechanically perturbing
individual library members, and an array of sensors
for measuring the response of each of the library
members to the mechanical perturbations. Library
members undergoing screening make up a sample array,
and individual library members constitute elements of
the sample array that are confined to specific
locations on the sample holder. During screening, the
apparatus mechanically perturbs individual library
members by displacing the sample array (sample holder)
and the array of probes. Typically, all of the elements
of the sample array are perturbed simultaneously, but
the apparatus also can also perturb individual or
groups of sample array elements sequentially. The
flexible apparatus and method can screen libraries of
materials based on many different bulk physical
properties, including Young's modulus (flexure,
uniaxial extension, biaxial compression, and shear);
hardness (indentation), failure (stress and strain at
failure, toughness), adhesion (tack, loop tack), and
flow (viscosity, meltflow indexing, and rheology),
among others.