Thermochemical Nanolithography
Thermochemical nanolithography (TCNL), a conceptually simple, yet potentially very adaptable scanning-probe technique, employs a resistively heated AFM cantilever to induce well defined chemical reactions in order to change surface functionality of thin polymer films. Such an approach is appealing as it is known that the thermal profile in the vicinity of a heated AFM tip can give rise to sharp thermal gradients and that chemical reaction rates increase exponentially with temperature.
A wealth of thermally activated chemistries can feasibly be employed to change the material¡¯s subsequent reactivity, surface energy, solubility, conductivity, or other property of interest as desired. Judicious choices of the physical properties of a material (e.g., polymer glass transition temperature, Tg) may afford a system wherein chemical changes can be performed either separately from, or accompanied by, topographical modification as required (for example, above Tg of a polymer, creation of substantial topographical changes (ripples) is exponentially amplified). Furthermore, the use of a material that can undergo multiple chemical reactions at significantly different temperatures renders the possibility of a multi state system wherein different functionalities can be addressed at different temperatures.
