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Title: Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework

Abstract

Nanoscale UiO-66 Zr6(OH)4O4(C8O4H4)6 has been synthesized with a series of carboxylic acid modulators, R-COOH (where R = H, CH3, CF3, and CHCl2). The phase purity and size of each MOF was confirmed by powder X-ray diffraction, BET surface area analysis, and scanning transmission electron microscopy (STEM). Size control of UiO-66 crystals from 20 nm to over 1 μm was achieved, and confirmed by STEM. The colloidal stability of each MOF was evaluated by dynamic light scattering and was found to be highly dependent on the modulator conditions utilized in the synthesis, with both lower pKa and higher acid concentration resulting in more stable structures. Furthermore, STEM was carried out on both colloidally stable samples and those that exhibited a large degree of aggregation, which allowed for visualization of the different degrees of dispersion of the samples. The use of modulators at higher concentrations and with lower pKas leads to the formation of more defects, as a consequence of terephthalic acid ligands being replaced by modulator molecules, thereby enhancing the colloidal stability of the UiO-66 nanoparticles. These findings could have a significant impact on nanoscale MOF material syntheses and applications, especially in the areas of catalysis and drug delivery.

Authors:
; ; ;  [1]; ORCiD logo; ORCiD logo [2]; ORCiD logo [1]
  1. Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
  2. Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
U.S. AIR FORCE- OFFICE OF SCIENTIFIC RESEARCH
OSTI Identifier:
1418044
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 39
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE

Citation Formats

Morris, William, Wang, Shunzhi, Cho, David, Auyeung, Evelyn, Li, Peng, Farha, Omar K., and Mirkin, Chad A.. Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework. United States: N. p., 2017. Web. doi:10.1021/acsami.7b01040.
Morris, William, Wang, Shunzhi, Cho, David, Auyeung, Evelyn, Li, Peng, Farha, Omar K., & Mirkin, Chad A.. Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework. United States. doi:10.1021/acsami.7b01040.
Morris, William, Wang, Shunzhi, Cho, David, Auyeung, Evelyn, Li, Peng, Farha, Omar K., and Mirkin, Chad A.. Fri . "Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework". United States. doi:10.1021/acsami.7b01040.
@article{osti_1418044,
title = {Role of Modulators in Controlling the Colloidal Stability and Polydispersity of the UiO-66 Metal–Organic Framework},
author = {Morris, William and Wang, Shunzhi and Cho, David and Auyeung, Evelyn and Li, Peng and Farha, Omar K. and Mirkin, Chad A.},
abstractNote = {Nanoscale UiO-66 Zr6(OH)4O4(C8O4H4)6 has been synthesized with a series of carboxylic acid modulators, R-COOH (where R = H, CH3, CF3, and CHCl2). The phase purity and size of each MOF was confirmed by powder X-ray diffraction, BET surface area analysis, and scanning transmission electron microscopy (STEM). Size control of UiO-66 crystals from 20 nm to over 1 μm was achieved, and confirmed by STEM. The colloidal stability of each MOF was evaluated by dynamic light scattering and was found to be highly dependent on the modulator conditions utilized in the synthesis, with both lower pKa and higher acid concentration resulting in more stable structures. Furthermore, STEM was carried out on both colloidally stable samples and those that exhibited a large degree of aggregation, which allowed for visualization of the different degrees of dispersion of the samples. The use of modulators at higher concentrations and with lower pKas leads to the formation of more defects, as a consequence of terephthalic acid ligands being replaced by modulator molecules, thereby enhancing the colloidal stability of the UiO-66 nanoparticles. These findings could have a significant impact on nanoscale MOF material syntheses and applications, especially in the areas of catalysis and drug delivery.},
doi = {10.1021/acsami.7b01040},
journal = {ACS Applied Materials and Interfaces},
number = 39,
volume = 9,
place = {United States},
year = {Fri Apr 07 00:00:00 EDT 2017},
month = {Fri Apr 07 00:00:00 EDT 2017}
}