A detachable SERS active cellulose film: a minimally invasive approach to the study of painting lakes

The design and synthesis of a tailor-made surface-enhanced Raman scattering (SERS) active film that is fabricated to be removable from the surface of an artwork under study following effective measurements is detailed. It is shown that silver nanoparticles prepared by green chemical reduction with glucose can be effectively doped into a methylcellulose (MC) matrix for the formation of a gel, which can be subsequently applied to a minute area (ca 1-1.5 mm) of an artwork without posing a threat to its integrity. Studies have been aimed at characterizing this film's chemical and physical properties, with regard to the stability of the nanoparticles dispersed within the MC, the ease of application of the viscous gel, its speed of drying and the transparency of the dry film for SERS measurements. Importantly, results have led to reproducible SERS enhancements of the order 10(3)-10(4) for studies carried out on reference laboratory dye components and unvarnished mock-paintings. Techniques including optical and scanning electron microscopy were used to monitor the drying of the film and its resulting morphology, as well as to map the distribution of silver nanoparticles in the film so as to account for any visual modification to the underlying surface upon film removal. Copyright (C) 2011 John Wiley & Sons, Ltd.