A Supra-monolayer Nanopattern for Organic Nanoparticle Array Deposition

Abstract

Nanopatterns have applications in many areas including sensors, optoelectronics, and crystallization screening. Particle lithography is a convenient method to manufacture nanoring nanopatterns based on organosilane surface chemistry. The pattern thickness is generally limited to the monolayer thickness. This work is focused on the chemical vapor deposition conditions that yield nanopatterns with multilayer thickness. The supra-monolayer n-octadecyltrichlorosilane (OTS) nanoring patterns are made using polystyrene particle lithography. The supra-monolayer nanopatterns are used as "nano-flasks" to deposit and nucleate nanoparticles of small organic molecules including n-docosane, aspirin, and clarithromycin. The supra-monolayer OTS nanopattern is an effective template for nanoparticle array deposition of all three chemicals with high degree of fidelity to the substrate pattern. The nanoparticle size is varied by solution concentration. The preferential deposition of the organic molecules inside the nanoring is attributed to the dewetting of the liquid film on the nanopattern. The dewetting process effectively distributes the liquid film among the "nano-flasks" so that millions of solution experiments can be carried out in isolated droplets with droplet volume as small as 1×10(-10) nL. The research demonstrates a method to manufacture "nano-flask" arrays for high-throughput nanoparticle deposition trials and manufacture of monodisperse organic/drug nanoparticles through self-assembly.

Surface-Directed Synthesis of Erbium-Doped Yttrium Oxide Nanoparticles within Organosilane Zeptoliter Containers

“…16−18 Particle lithography can be used to prepare surface molds of SAMs to define sites for the deposition of nanomaterials and to provide spatial separation during subsequent steps of drying or heating. The photoluminescent properties of NaYF 4 :Yb,Er rare earth nanoparticles prepared using particle lithography to generate periodically arranged rings of nanoparticles was investigated by Mullen et al 19 Nanorings of n-octadecyltrichlorosilane (OTS) were used as sites to nucleate nanoparticles of small organic molecules such as n-docosane, aspirin, and clarithromycin prepared using particle lithography by Wang et al 20 Erbium-doped yttrium oxide nanoparticles have interesting luminescent properties such as intense cathodoluminescence and photoluminescence. 7,21 Nanomaterials of yttrium oxide doped with rare earth elements have been prepared by flame spray pyrolysis (Eu:Y 2 O 3 ), 7 thermal decomposition of a polymeric resin, 22 atomic layer deposition, 23 gas-phase condensation, 24 flux, 25 combustion, 26−28 solvothermal 29 and hydrothermal methods, 30−36 alkalide reduction, 37 solutionbased sol−gel processes, 38 emulsion techniques, 39−41 precipitation, 42−44 and electrochemical 45 methods.…”

Surface Coupling of Octaethylporphyrin with Silicon Tetrachloride

“…Ring-shaped morphologies have been reported previously for samples prepared by approaches with colloidal lithography. 62,67,78−80,84,85 A sample was prepared with oven drying by heating a masked Si(111) substrate at 150 °C for 20 h and then immediately placing the dried sample into a solution of OEP and SiCl 4 in chloroform for 5 h. By heating the substrate for longer intervals (up to 20 h), most of the water throughout the surface was driven to evaporate, and only nanoscopic residues of moisture persisted in the water meniscus sites at the base of the particles. The shapes and arrangement of the nanorings are shown in Figure 4 where a few trace adsorbates of Si-OEP can be detected in areas in between the rings.…”

“…In previous studies, we have successfully used OTS as a generic matrix with colloidal lithography to pattern 4-(chloromethyl)phenyl trichlorosilane, 86 polymers, 57 proteins, 61,87 rare-earth oxide nanoparticles, 88 as well as freebase and metallated porphyrins. 89 Methyl-terminated decyltrichlorosilane was used as a resist for patterning OTS by Brownfield et al 79 Patterns of n-docosane, aspirin, and clarithromycin were produced within a matrix of OTS, as reported by Wang et al 80 Beyond colloidal lithography, matrices of OTS have also been used with other nanolithography approaches for patterning organic films to attach carbon nanotubes, 90 metal wires, 91 nanoparticles, 92,93 and proteins. 94 The steps for spatially selective deposition of Si-OEP into uncovered nanoholes within an OTS film are depicted in Figure 5.…”

“…Protocols of colloidal lithography employ a surface mask of latex or silica spheres and have been applied for patterning materials such as polymers, , proteins, − rare-earth nanomaterials, , nanoparticles, , metals, − organosilanes, − and organothiols . We are developing protocols using colloidal lithography to prepare surface films and nanostructures with porphyrins that are covalently bound to silicon substrates.…”

Periodic Arrangement of Lipopolysaccharides Nanostructures Accelerates and Enhances the Maturation Processes of Dendritic Cells

“…Second, a series of surface-bound LPS was produced. Hierarchical LPS structures with designed periodicity were produced on silicon surfaces: productions of arrays of OTS were inlaid in OEG-silane SAMs via particle lithography, ,,, followed by immobilization of LPS onto the OTS nanostructures . The immobilization of LPS onto methyl-terminated OTS nanostructures was selective, as the surrounding OEG-silane SAM resisted protein adhesion. , The hierarchical LPS structures were characterized with nanometer resolution using AFM, as shown in Figure .…”