Patterned thin films of polymers

Figure 11 Schematic description of the procedure for patterning thin films of PEI on the surface of a SAM using xCP and a chemical reaction. The scheme suggests the composition of the SAM, but not the conformation of the groups in it it also makes no attempt to represent either the conformation of the polymer or the distribution of functional groups on the polymer backbone.

PEI is a hydrophilic polymer, it is essential to make the hydrophobic PDMS stamp hydrophilic using oxygen plasma prior to inking in order to form continuous, patterned thin films of PEI on the surface [206]. PIERS studies further show that PEI is covalently linked to the SAM by amide bonds and that the PEI films are thus more stable under both acidic and basic conditions than are polymers physically adsorbed on SAMs of carboxylic acids. 

Phase separation can emerge spontaneously in thin films of polymer blend, and it is this thermodynamically driven phase-separation process that produces the patterning of thin polymer blend films. It can be induced by several parameters, each with critical values, including (i) the ratio between the components [10,22] (ii) the demixing temperature [12] and (iii) the chemical nature of the solvent. 

More recendy, the interest in thin films of polymer blend has been revived by directed phase separadon in the presence of electric fields. Electrohydrodynamic instability of the interface between two dielectric fluids generates patterns of oriented microdomains with a wavelength determined by the interfadal energy and the electric field gradient at the interface. When combined with a topographically patterned electrode, this... 

---