Control of Alkanethiolate Monolayer Structure Using Vapor-Phase Annealing

Abstract

We describe an annealing procedure for self-assembled monolayers (SAMs) that uses vapor-phase molecules to modify the local domain structure. Existing SAMs of decanethiolate on Au{111} were annealed using vapor-phase dodecanethiol molecules, so that the original and newly introduced molecules could be distinguished using scanning tunneling microscopy (STM). Molecules deposited from the vapor phase inserted at existing monolayer defect sites and domain boundaries, and at substrate step edges forming discrete network-like domains. The SAM molecular lattice can be preserved across molecular terrace boundaries between the decanethiolate and dodecanethiolate domains. Candidate molecular electronic component molecules were inserted from solution in the decanethiolate matrix as isolated molecules. These inserted molecules could then be surrounded by dodecanethiolate molecules introduced from the vapor phase, thus demonstrating a method for controlling the local environment of inserted molecules.

Holey Graphene as a Weed Barrier for Molecules

“…The same sample is then exposed to the vapor of a 1 mM ethanolic solution of the self-assembling cage molecule 1-adamantanethiol (1AD) and subsequently imaged. 54 The diamondoid 1AD is ideal for an initial patterning test, in that it is commercially available, forms well-ordered monolayers with few defects (due to limited degrees of freedom), and has a well-defined structure. [55][56][57][58] Scanning tunneling micrographs recorded after deposition show islands of molecular protrusions consistent with the diameters of the pores ( Figure 4).…”

Biospecific Recognition of Tethered Small Molecules Diluted in Self‐Assembled Monolayers

“…While no lithographic techniques exist for the deterministic placement of single small molecules, our insertion strategy solves this problem by controlling the types and densities of defects into which to place single, isolated molecules in the SAM matrix. [5,11,12] This insertion method has also been used recently to advantage for controlled dendrimer growth on surfaces. [27] In the present application, isolated tethered small-molecule-probe-functionalized surfaces have been designed to capture proteins that interact with them and to screen nucleic acid libraries for aptamers.…”

Microcontact insertion printing

“…Here, we report a technique called "microcontact insertion printing" ͑CIP͒ where isolated molecules are inserted into the defects of a preexisting monolayer in regions that are contacted by a patterned elastomeric stamp. By tuning the degree of molecular insertion into and exchange between the patterned molecules and the preexisting self-assembled monolayer ͑SAM͒, 7,[9][10][11] we can precisely control the isolation and dilution of the inserted molecules and the molecular composition of the patterned SAM. We also prevent lateral surface diffusion of the inserted molecules so as to maintain their isolation, and to prevent both phase separation 7,12,13 and pattern dissolution.…”

“…This location preference is attributed to the patterned molecules having greater access to the substrate at the SAM defects and is consistent with our earlier observations of solution-and vapor-phase insertions. 7,[9][10][11] The extent of insertion can be influenced by tuning the stamping duration and the concentration of C12 on the PDMS stamp. Figure 3 shows a matrix of representative STM images of C8 SAMs printed with an unpatterned PDMS stamp coated with C12 molecules using different combinations of stamping times and C12 concentrations.…”