Tuning interfacial interactions for bottom‐up assembly of surface‐anchored metal‐organic frameworks to tailor film morphology and pattern surface features

Abstract

Surface-anchored metal-organic frameworks (surMOFs) integrate nanoporous supramolecular MOF materials directly into architectures for applications such as gas storage, chemical sensing, and energy storage. Layer-by-layer solution-phase deposition of the MOF-14 components (1,3,5-tris(4-carboxyphenyl)benzene and copper (II) dimers, respectively) produces a porous and conformal film on carboxylterminated self-assembled monolayers (SAMs). In this research, the formation of ultrathin (less than 25 nm) surMOF films on codeposited bicomponent SAMs and microcontact printed SAMs is investigated by atomic force microscopy, ellipsometry, infrared spectroscopy, and contact angle goniometry. SAMs composed of methyl-terminated alkanethiols assembled on gold substrates inhibit surMOF formation, whereas carboxyl-terminated alkanethiols promote MOF-14-based film growth. To tune the density of carboxyl groups that anchor the film, methyl-and carboxylterminated alkanethiols of varying concentrations are codeposited on gold. This systematic study demonstrates how surMOF film formation and morphology are impacted by these SAMs with mixed surface functionalities. Chemical patterning methods for SAMs, such as microcontact printing (µCP), commonly have mixed chemical functionalities within certain regions of the pattern. Insights gained regarding how mixed surface functionalities affect surMOF film formation are applied herein to optimize the µCP method to produce chemically patterned SAMs that selectively direct surMOF assembly to produce high-quality surMOF film features.

Fluorophor Embedded MOFs Steering Gas Ultra‐Recognition

“…[8] MOF (Metal-Organic Framework) is a unique crystalline porous material formed by the self-assembly of metal nodes (metal ions or clusters) and organic ligands through coordination bonds. [9] Chemical sensing based on MOF materials has emerged as a particularly promising gas-sensing Scheme 1. Schematic of preparation of high-performance sensing films by fluorophor-embedded MOFs.…”

Mesoporous-Structure MOF-14-Based QCM p-Xylene Gas Sensor

“…As a classical microporous material, MOF-14 [32][33][34] has a stable structure and a mild metal site Cu 2+ . Therefore, it could possess strong adsorption on the electron-rich Lewis alkaline gases such as those of the benzene series.…”

Impact of Surface Functionalization and Deposition Method on Cu-BDC surMOF Formation, Morphology, Crystallinity, and Stability

“…To incorporate surMOF systems into device architectures, the fundamentals of surMOF film formation must be explored and understood for a variety of MOF systems as well as for different deposition methods to further understand how film growth can be tailored to meet design requirements. The study herein builds on the few studies available in the literature regarding the formation of surMOFs examining the growth mechanism through a systematic investigation of their nanoscale surface features. ,,,− This research investigates the growth of Cu-BDC (copper benzene-1,4-dicarboxylate) surMOF films using atomic force microscopy (AFM) complemented with powder X-ray diffraction (XRD), IR spectroscopy, and ellipsometry analysis. Cu-BDC was selected for this investigation because it is a well-studied MOF powder with applications for catalysis and sensing technology. − This MOF system is also called Cu-MOF-2 because it is an analogue of MOF-2, which contains Zn.…”

“…The study herein builds on the few studies available in the literature regarding the formation of surMOFs examining the growth mechanism through a systematic investigation of their nanoscale surface features. 14 , 17 , 19 , 27 − 30 This research investigates the growth of Cu-BDC (copper benzene-1,4-dicarboxylate) surMOF films using atomic force microscopy (AFM) complemented with powder X-ray diffraction (XRD), IR spectroscopy, and ellipsometry analysis. Cu-BDC was selected for this investigation because it is a well-studied MOF powder with applications for catalysis and sensing technology.…”