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Organic Functionalized Graphene Oxide Behavior in Water

Surface modified graphene oxide (GO) has received broad interest as a potential platform material for sensors, membranes, and sorbents, among other environmental applications. However, compared to parent (unmodified) GO, there is a dearth of information regarding the behavior of subsequently (second...

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Autores principales: Kim, Changwoo, Lee, Junseok, Wang, Will, Fortner, John
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353123/
https://www.ncbi.nlm.nih.gov/pubmed/32599799
http://dx.doi.org/10.3390/nano10061228
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author Kim, Changwoo
Lee, Junseok
Wang, Will
Fortner, John
author_facet Kim, Changwoo
Lee, Junseok
Wang, Will
Fortner, John
author_sort Kim, Changwoo
collection PubMed
description Surface modified graphene oxide (GO) has received broad interest as a potential platform material for sensors, membranes, and sorbents, among other environmental applications. However, compared to parent (unmodified) GO, there is a dearth of information regarding the behavior of subsequently (secondary) modified GO, other than bulk natural organic matter (NOM) coating(s). Here, we systematically explore the critical role of organic functionalization with respect to GO stability in water. Specifically, we synthesized a matrix of GO-based materials considering a carefully chosen range of bound organic molecules (hydrophobic coatings: propylamine, tert-octylamine, and 1-adamantylamine; hydrophilic coatings: 3-amino-1-propanol and 3-amino-1-adamantanol), so that chemical structures and functional groups could be directly compared. GO (without organic functionalization) with varying oxidation extent(s) was also included for comparison. The material matrix was evaluated for aqueous stability by comparing critical coagulation concentration (CCC) as a function of varied ionic strength and type (NaCl, CaCl(2), MgCl(2), and MgSO(4)) at pH 7.0. Without surface derivatization (i.e., pristine GO), increased stability was observed with an increase in the GO oxidation state, which is supported by plate–plate Derjaguin, Landau, Verwey and Overbeek (DLVO) energy interaction analyses. For derivatized GO, we observed that hydrophilic additions (phi-GO) are relatively more stable than hydrophobic organic coated GO (pho-GO). We further explored this by altering a single OH group in the adamantane-x structure (3-amino-1-adamantanol vs. 1-adamantylamine). As expected, Ca(2+) and monovalent co-ions play an important role in the aggregation of highly oxidized GO (HGO) and phi-GO, while the effects of divalent cations and co-ions were less significant for pho-GO. Taken together, this work provides new insight into the intricate dynamics of GO-based material stability in water as it relates to surface functionalization (surface energies) and ionic conditions including type of co- and counter-ion, valence, and concentration.
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spelling pubmed-73531232020-07-15 Organic Functionalized Graphene Oxide Behavior in Water Kim, Changwoo Lee, Junseok Wang, Will Fortner, John Nanomaterials (Basel) Article Surface modified graphene oxide (GO) has received broad interest as a potential platform material for sensors, membranes, and sorbents, among other environmental applications. However, compared to parent (unmodified) GO, there is a dearth of information regarding the behavior of subsequently (secondary) modified GO, other than bulk natural organic matter (NOM) coating(s). Here, we systematically explore the critical role of organic functionalization with respect to GO stability in water. Specifically, we synthesized a matrix of GO-based materials considering a carefully chosen range of bound organic molecules (hydrophobic coatings: propylamine, tert-octylamine, and 1-adamantylamine; hydrophilic coatings: 3-amino-1-propanol and 3-amino-1-adamantanol), so that chemical structures and functional groups could be directly compared. GO (without organic functionalization) with varying oxidation extent(s) was also included for comparison. The material matrix was evaluated for aqueous stability by comparing critical coagulation concentration (CCC) as a function of varied ionic strength and type (NaCl, CaCl(2), MgCl(2), and MgSO(4)) at pH 7.0. Without surface derivatization (i.e., pristine GO), increased stability was observed with an increase in the GO oxidation state, which is supported by plate–plate Derjaguin, Landau, Verwey and Overbeek (DLVO) energy interaction analyses. For derivatized GO, we observed that hydrophilic additions (phi-GO) are relatively more stable than hydrophobic organic coated GO (pho-GO). We further explored this by altering a single OH group in the adamantane-x structure (3-amino-1-adamantanol vs. 1-adamantylamine). As expected, Ca(2+) and monovalent co-ions play an important role in the aggregation of highly oxidized GO (HGO) and phi-GO, while the effects of divalent cations and co-ions were less significant for pho-GO. Taken together, this work provides new insight into the intricate dynamics of GO-based material stability in water as it relates to surface functionalization (surface energies) and ionic conditions including type of co- and counter-ion, valence, and concentration. MDPI 2020-06-24 /pmc/articles/PMC7353123/ /pubmed/32599799 http://dx.doi.org/10.3390/nano10061228 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kim, Changwoo
Lee, Junseok
Wang, Will
Fortner, John
Organic Functionalized Graphene Oxide Behavior in Water
title Organic Functionalized Graphene Oxide Behavior in Water
title_full Organic Functionalized Graphene Oxide Behavior in Water
title_fullStr Organic Functionalized Graphene Oxide Behavior in Water
title_full_unstemmed Organic Functionalized Graphene Oxide Behavior in Water
title_short Organic Functionalized Graphene Oxide Behavior in Water
title_sort organic functionalized graphene oxide behavior in water
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353123/
https://www.ncbi.nlm.nih.gov/pubmed/32599799
http://dx.doi.org/10.3390/nano10061228
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