Nanostructures formed by the surface self-assembly of 4-(chloromethyl)phenyltrichlorosilane studied with selected solvents and temperatures

Abstract

The self-assembly and growth of 4-(chloromethyl)-phenyltrichlorosilane (CMPS) nanostructures within nanoholes that were formed within a thin film of octadecyltrichlorosilane (OTS) was studied ex situ using atomic force microscopy (AFM). The effects of selected solvents and temperatures on the growth of the CMPS were investigated to gain insight into the mechanisms of the surface assembly and self-polymerization of CMPS. Surface platforms of nanoholes were generated within a thin film of OTS using particle lithography combined with immersion steps. The film of OTS provided a resist for preventing nonspecific adsorption of CMPS in areas surrounding the nanoholes. The uncovered areas of substrate within the nanoholes were used to direct the self-assembly of CMPS. Nanopatterns were imaged using AFM after key steps of the nanofabrication procedure. The samples were immersed in solutions of CMPS that were prepared with selected solvents that included toluene, bicyclohexyl, and dichloromethane. The size and morphology of CMPS nanostructures were influenced by the nature of the solvent, and nonpolar solvents were better suited for reproducibly growing regular nanostructures. For nanostructures of CMPS grown within nanoholes, the rate of CMPS self-assembly and growth exhibited differences at the molecular level for temperatures ranging from −4 to 20 °C. The analysis of the height and width of CMPS nanopatterns reveals that multiple layers formed with taller surface structures being formed at higher temperatures. Particle lithography provides a useful tool for studying chemical reactions at the nanometer scale since basic steps of sample preparation can used to make multiple nanopatterns for surface measurements under controlled environmental conditions.