PH-responsive cellulose nanocrystal gels and nanocomposites

Amanda E. Way; Lorraine Hsu; Kadhiravan Shanmuganathan; Christoph Weder; Stuart J. Rowan

doi:10.1021/mz3003006

PH-responsive cellulose nanocrystal gels and nanocomposites

Amanda E. Way, Lorraine Hsu, Kadhiravan Shanmuganathan, Christoph Weder, Stuart J. Rowan^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

186 Citations (Scopus)

Abstract

We show that functionalization of the surface of cellulose nanocrystals (CNCs) with either carboxylic acid (CNC-CO₂H) or amine (CNC-NH ₂) moieties renders the CNCs pHresponsive. At low pH, where the amine groups are protonated, CNC-NH₂ forms aqueous dispersions in water on account of electrostatic repulsions of the ammonium moieties inhibiting aggregation. However, a transition to hydrogels is observed at higher pH where the CNC-NH₂ are neutral and the attractive forces based on hydrogen bonding dominate. The opposite behavior is observed for CNC-CO₂H, which are dispersible at high pH and form gels in an acidic environment. We further show that these pH-responsive CNCs can be incorporated into a poly(vinyl acetate) matrix to yield mechanically adaptive pH-responsive nanocomposite films.

Original language	English
Pages (from-to)	1001-1006
Number of pages	6
Journal	ACS Macro Letters
Volume	1
Issue number	8
DOIs	https://doi.org/10.1021/mz3003006
Publication status	Published - 2012
Externally published	Yes

ASJC Scopus subject areas

Organic Chemistry
Materials Chemistry
Polymers and Plastics
Inorganic Chemistry

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abstract = "We show that functionalization of the surface of cellulose nanocrystals (CNCs) with either carboxylic acid (CNC-CO2H) or amine (CNC-NH 2) moieties renders the CNCs pHresponsive. At low pH, where the amine groups are protonated, CNC-NH2 forms aqueous dispersions in water on account of electrostatic repulsions of the ammonium moieties inhibiting aggregation. However, a transition to hydrogels is observed at higher pH where the CNC-NH2 are neutral and the attractive forces based on hydrogen bonding dominate. The opposite behavior is observed for CNC-CO2H, which are dispersible at high pH and form gels in an acidic environment. We further show that these pH-responsive CNCs can be incorporated into a poly(vinyl acetate) matrix to yield mechanically adaptive pH-responsive nanocomposite films.",

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T1 - PH-responsive cellulose nanocrystal gels and nanocomposites

AU - Way, Amanda E.

AU - Hsu, Lorraine

AU - Shanmuganathan, Kadhiravan

AU - Weder, Christoph

AU - Rowan, Stuart J.

PY - 2012

Y1 - 2012

N2 - We show that functionalization of the surface of cellulose nanocrystals (CNCs) with either carboxylic acid (CNC-CO2H) or amine (CNC-NH 2) moieties renders the CNCs pHresponsive. At low pH, where the amine groups are protonated, CNC-NH2 forms aqueous dispersions in water on account of electrostatic repulsions of the ammonium moieties inhibiting aggregation. However, a transition to hydrogels is observed at higher pH where the CNC-NH2 are neutral and the attractive forces based on hydrogen bonding dominate. The opposite behavior is observed for CNC-CO2H, which are dispersible at high pH and form gels in an acidic environment. We further show that these pH-responsive CNCs can be incorporated into a poly(vinyl acetate) matrix to yield mechanically adaptive pH-responsive nanocomposite films.

AB - We show that functionalization of the surface of cellulose nanocrystals (CNCs) with either carboxylic acid (CNC-CO2H) or amine (CNC-NH 2) moieties renders the CNCs pHresponsive. At low pH, where the amine groups are protonated, CNC-NH2 forms aqueous dispersions in water on account of electrostatic repulsions of the ammonium moieties inhibiting aggregation. However, a transition to hydrogels is observed at higher pH where the CNC-NH2 are neutral and the attractive forces based on hydrogen bonding dominate. The opposite behavior is observed for CNC-CO2H, which are dispersible at high pH and form gels in an acidic environment. We further show that these pH-responsive CNCs can be incorporated into a poly(vinyl acetate) matrix to yield mechanically adaptive pH-responsive nanocomposite films.

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PH-responsive cellulose nanocrystal gels and nanocomposites

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