Effects of humidity and temperature on laser-assisted dip-pen nanolithography array using molecular dynamics simulations

• Published in: Journal of colloid and interface science Vol. 372; no. 1; pp. 170 - 175
• Main Authors: Wu, Cheng-Da, Fang, Te-Hua, Wu, Tsung-Tse
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.04.2012; Elsevier
• Subjects: Array; Chemistry; cooling; Deposition; Diffusion coefficient; diffusivity; Dip-pen nanolithography; energy; Exact sciences and technology; General and physical chemistry; Heating rate; Humidity; Molecular dynamics; Nanomaterials; Nanostructure; Simulation; Temperature; Array; Molecular dynamics; Dip-pen nanolithography; Temperature; Humidity; Water; Patterning; Growth; Heating rate; Saturation; Ink; Alkanethiol; Deposition rate; Laser pulse; Simulation; Heating; Efficiency; Binding energy; Laser; Diffusion coefficient; Diffusion; Deposition; Surface energy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2012.01.038

[Display omitted] ► The number of molecules transferred increases significantly with increasing humidity. ► The number of transferred ink molecules and their diffusion ability are highest at the dwell stage. ► The transfer efficiency of the DPN process improves as the system humidity increases to saturation. ► Vapor water molecules limit meniscus growth for temperatures above 300K. Two-dimensional dip-pen nanolithography (DPN) combined with laser-assisted heating is studied using molecular dynamics (MDs) simulations. The effects of humidity, deposition temperature, heating rate (laser-assisted patterning), and cooling rate on ink molecules are evaluated in terms of molecular transference, alkanethiol meniscus characteristics, surface binding energy, number of transferred chains, pattern characteristics, and the diffusion coefficient of ink molecules. The simulation results clearly show that the number of molecules transferred significantly increases with increasing humidity, which leads to increases in meniscus size and pattern size. The surface binding energy decreases and the diffusion coefficient of ink molecules increases with increasing humidity and deposition temperature. The dwell stage has the largest number of molecules transferred and the largest diffusion distance of ink molecules. The number of vaporous water molecules increases when the temperature is above 300K, which limits meniscus growth and leads to unstable deposition. The DPN transfer efficiency can be significantly enhanced by increasing the laser pulse energy/heating rate. The transfer efficiency improves as the system humidity increases to saturation (374 water molecules).