Octylamine-Modified Cellulose Nanocrystal-Enhanced Stabilization of Pickering Emulsions for Self-Healing Composite Coatings

Guofan Xu; Rinat Nigmatullin; Todor T. Koev; Yaroslav Z. Khimyak; Ian. P. Bond; Stephen J. Eichhorn

doi:10.1021/acsami.2c01324

Octylamine-Modified Cellulose Nanocrystal-Enhanced Stabilization of Pickering Emulsions for Self-Healing Composite Coatings

Guofan Xu, Rinat Nigmatullin, Todor T. Koev, Yaroslav Z. Khimyak, Ian. P. Bond, Stephen J. Eichhorn^*

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

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Abstract

Linseed oil-in-water Pickering emulsions are stabilized by both sulfated CNCs (sCNCs) and octylamine-modified CNCs (oCNCs). oCNCs with hydrophobic moieties grafted on the surfaces of otherwise intact nanocrystals provided emulsions exhibiting stronger resistance to creaming of oil droplets, compared with unmodified sCNCs. sCNCs were not able to completely stabilize linseed oil in water at low CNC concentrations while oCNCs provided emulsions with no unemulsified oil residue at the same concentrations. Oil droplets in oCNC emulsions were smaller than those in samples stabilized by sCNCs, corresponding with an increased hydrophobicity of oCNCs. Cryo-SEM imaging of stabilized droplets demonstrated the formation of a CNC network at the oil–water interface, protecting the oil droplets from coalescence even after compaction under centrifugal force. These oil droplets, protected by a stabilized CNC network, were dispersed in a water-based commercial varnish, to generate a composite coating. Scratches made on these coatings self-healed as a result of the reaction of the linseed oil bled from the damaged droplets with oxygen. The leakage and drying of the linseed oil at the location of the scratches happened without intervention and was accelerated by the application of heat.

Original language	English
Pages (from-to)	12722–12733
Number of pages	12
Journal	ACS Applied Materials and Interfaces
Volume	14
Issue number	10
Early online date	7 Mar 2022
DOIs	https://doi.org/10.1021/acsami.2c01324
Publication status	Published - 16 Mar 2022

Bibliographical note

Funding Information:
S.J.E. would like to thank the Engineering and Physical Sciences Research Council for funding (Grant No. V002651/1). T.T.K. acknowledges the support of the UKRI Future Leaders Fellowship awarded to M. Wallace (MR/T044020/1). We are grateful to the UEA’s Faculty of Science NMR facility.

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

Keywords

cellulose nanocrystals
octylamine
linseed oil
Pickering emulsion

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title = "Octylamine-Modified Cellulose Nanocrystal-Enhanced Stabilization of Pickering Emulsions for Self-Healing Composite Coatings",

abstract = "Linseed oil-in-water Pickering emulsions are stabilized by both sulfated CNCs (sCNCs) and octylamine-modified CNCs (oCNCs). oCNCs with hydrophobic moieties grafted on the surfaces of otherwise intact nanocrystals provided emulsions exhibiting stronger resistance to creaming of oil droplets, compared with unmodified sCNCs. sCNCs were not able to completely stabilize linseed oil in water at low CNC concentrations while oCNCs provided emulsions with no unemulsified oil residue at the same concentrations. Oil droplets in oCNC emulsions were smaller than those in samples stabilized by sCNCs, corresponding with an increased hydrophobicity of oCNCs. Cryo-SEM imaging of stabilized droplets demonstrated the formation of a CNC network at the oil–water interface, protecting the oil droplets from coalescence even after compaction under centrifugal force. These oil droplets, protected by a stabilized CNC network, were dispersed in a water-based commercial varnish, to generate a composite coating. Scratches made on these coatings self-healed as a result of the reaction of the linseed oil bled from the damaged droplets with oxygen. The leakage and drying of the linseed oil at the location of the scratches happened without intervention and was accelerated by the application of heat.",

keywords = "cellulose nanocrystals, octylamine, linseed oil, Pickering emulsion",

author = "Guofan Xu and Rinat Nigmatullin and Koev, {Todor T.} and Khimyak, {Yaroslav Z.} and Bond, {Ian. P.} and Eichhorn, {Stephen J.}",

note = "Funding Information: S.J.E. would like to thank the Engineering and Physical Sciences Research Council for funding (Grant No. V002651/1). T.T.K. acknowledges the support of the UKRI Future Leaders Fellowship awarded to M. Wallace (MR/T044020/1). We are grateful to the UEA{\textquoteright}s Faculty of Science NMR facility. Publisher Copyright: {\textcopyright} 2022 American Chemical Society. All rights reserved.",

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AU - Xu, Guofan

AU - Nigmatullin, Rinat

AU - Koev, Todor T.

AU - Khimyak, Yaroslav Z.

AU - Bond, Ian. P.

AU - Eichhorn, Stephen J.

N1 - Funding Information: S.J.E. would like to thank the Engineering and Physical Sciences Research Council for funding (Grant No. V002651/1). T.T.K. acknowledges the support of the UKRI Future Leaders Fellowship awarded to M. Wallace (MR/T044020/1). We are grateful to the UEA’s Faculty of Science NMR facility. Publisher Copyright: © 2022 American Chemical Society. All rights reserved.

PY - 2022/3/16

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N2 - Linseed oil-in-water Pickering emulsions are stabilized by both sulfated CNCs (sCNCs) and octylamine-modified CNCs (oCNCs). oCNCs with hydrophobic moieties grafted on the surfaces of otherwise intact nanocrystals provided emulsions exhibiting stronger resistance to creaming of oil droplets, compared with unmodified sCNCs. sCNCs were not able to completely stabilize linseed oil in water at low CNC concentrations while oCNCs provided emulsions with no unemulsified oil residue at the same concentrations. Oil droplets in oCNC emulsions were smaller than those in samples stabilized by sCNCs, corresponding with an increased hydrophobicity of oCNCs. Cryo-SEM imaging of stabilized droplets demonstrated the formation of a CNC network at the oil–water interface, protecting the oil droplets from coalescence even after compaction under centrifugal force. These oil droplets, protected by a stabilized CNC network, were dispersed in a water-based commercial varnish, to generate a composite coating. Scratches made on these coatings self-healed as a result of the reaction of the linseed oil bled from the damaged droplets with oxygen. The leakage and drying of the linseed oil at the location of the scratches happened without intervention and was accelerated by the application of heat.

AB - Linseed oil-in-water Pickering emulsions are stabilized by both sulfated CNCs (sCNCs) and octylamine-modified CNCs (oCNCs). oCNCs with hydrophobic moieties grafted on the surfaces of otherwise intact nanocrystals provided emulsions exhibiting stronger resistance to creaming of oil droplets, compared with unmodified sCNCs. sCNCs were not able to completely stabilize linseed oil in water at low CNC concentrations while oCNCs provided emulsions with no unemulsified oil residue at the same concentrations. Oil droplets in oCNC emulsions were smaller than those in samples stabilized by sCNCs, corresponding with an increased hydrophobicity of oCNCs. Cryo-SEM imaging of stabilized droplets demonstrated the formation of a CNC network at the oil–water interface, protecting the oil droplets from coalescence even after compaction under centrifugal force. These oil droplets, protected by a stabilized CNC network, were dispersed in a water-based commercial varnish, to generate a composite coating. Scratches made on these coatings self-healed as a result of the reaction of the linseed oil bled from the damaged droplets with oxygen. The leakage and drying of the linseed oil at the location of the scratches happened without intervention and was accelerated by the application of heat.

KW - cellulose nanocrystals

KW - octylamine

KW - linseed oil

KW - Pickering emulsion

U2 - 10.1021/acsami.2c01324

DO - 10.1021/acsami.2c01324

M3 - Article (Academic Journal)

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SN - 1944-8244

VL - 14

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EP - 12733

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

IS - 10

ER -

Octylamine-Modified Cellulose Nanocrystal-Enhanced Stabilization of Pickering Emulsions for Self-Healing Composite Coatings

Abstract

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