Detection of functional states of molecularly imprinted thin films with multi-cycling nanoindentation

Molecular imprinting is a chemical technique for the production of molecule-specific cavities. Spin casting with amino acids, aromatic molecules, carbohydrates or pesticides used as template molecules produces thin, selectively imprinted films of nylon-6 and other polymers. The film recognition activity is clearly coordinated with the appearance of manometer-sized pores. The mechanical properties of the imprinted network reflect the various functional states of molecularly imprinted polymer films. Three specific functional states of the MIP were observed. Pores filled by template molecules may be distinguished from empty pores due to the variation in the elasticity modulus, the viscoelasticity and the hardness. The presence of the template molecule makes the polymer matrix stiffer due to strong hydrogen bonds (or other interactions) with the polymer chains. Films with empty pores have a higher viscoelasticity than those with filled pores. Changes in the polymer network are directly related to the nanomechanical properties and systematically studied in this work. (c) 2006 Elsevier Ltd. All rights reserved.