Solvent Induced Adhesion Interactions between Dichlorotriazine Films

This article reports adhesion interactions between silicon-supported dichlorotriazine films in various solvents. The formation, chemical composition, and thickness of the overlayer were analyzed by means of X-ray photoelectron spectroscopy (XPS). An atomic force microscopy (AFM) characterization was performed to evaluate the overlayer roughness. Adhesion interactions were measured using chemical force spectrometry (CFS). The purpose of the study is to understand the effect of solvents on the adhesion force between dichlorotriazine films. The tip surface adhesion forces measured in octane and cyclooctane were found to be relatively weak. Use of solvents that may participate in pi-pi interactions, such as toluene and trifluoromethyl benzene, as well as a potential monohalogen bond donor, such as CCl4, did not lead to significant increase in the tip surface forces. However, the adhesion forces increase considerably when measured in solvents that contain at least two ether groups, such as dioxane, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. These most important interactions in ether-type solvents are due to bridging of the solvent between the two surfaces. Molecular dynamics simulations of the functionalized surfaces are consistent with enhanced solvent bridging interactions when the solvent contains ether functional groups.