Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations
Sulfate groups on cellulose particles such as cellulose nanocrystals (CNCs) provide colloidal stability credit to electrostatic repulsion between the like-charged particles. The introduction of sodium counter cations on the sulfate groups enables drying of the CNC suspensions without irreversible ag...
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MDPI AG
2022-09-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/18/3131 |
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| author | Patrick Petschacher Reza Ghanbari Carina Sampl Helmar Wiltsche Roland Kádár Stefan Spirk Tiina Nypelö |
| author_facet | Patrick Petschacher Reza Ghanbari Carina Sampl Helmar Wiltsche Roland Kádár Stefan Spirk Tiina Nypelö |
| author_sort | Patrick Petschacher |
| collection | DOAJ |
| description | Sulfate groups on cellulose particles such as cellulose nanocrystals (CNCs) provide colloidal stability credit to electrostatic repulsion between the like-charged particles. The introduction of sodium counter cations on the sulfate groups enables drying of the CNC suspensions without irreversible aggregation. Less is known about the effect of other counter cations than sodium on extending the properties of the CNC particles. Here, we introduce the alkali metal counter cations, Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup>, Rb<sup>+</sup>, and Cs<sup>+</sup>, on sulfated CNCs without an ion exchange resin, which, so far, has been a common practice. We demonstrate that the facile ion exchange is an efficient method to exchange to any alkali metal cation of sulfate half esters, with exchange rates between 76 and 89%. The ability to form liquid crystalline order in rest was observed by the presence of birefringence patterns and followed the Hofmeister series prediction of a decreasing ability to form anisotropy with an increasing element number. However, we observed the K-CNC rheology and birefringence as a stand-out case within the series of alkali metal modifications, with dynamic moduli and loss tangent indicating a network disruptive effect compared to the other counter cations, whereas observation of the development of birefringence patterns in flow showed the absence of self- or dynamically-assembled liquid crystalline order. |
| first_indexed | 2024-03-09T22:59:24Z |
| format | Article |
| id | doaj.art-cbd5e137b6d84f0b99c35621c5b43460 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T22:59:24Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-cbd5e137b6d84f0b99c35621c5b434602023-11-23T18:06:01ZengMDPI AGNanomaterials2079-49912022-09-011218313110.3390/nano12183131Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter CationsPatrick Petschacher0Reza Ghanbari1Carina Sampl2Helmar Wiltsche3Roland Kádár4Stefan Spirk5Tiina Nypelö6Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, AustriaDepartment of Industrial Materials Science, Chalmers University of Technology, 41296 Gothenburg, SwedenInstitute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, AustriaInstitute of Analytical Chemistry and Food Chemistry, Graz University of Technology, 8010 Graz, AustriaDepartment of Industrial Materials Science, Chalmers University of Technology, 41296 Gothenburg, SwedenInstitute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, AustriaDepartment of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, SwedenSulfate groups on cellulose particles such as cellulose nanocrystals (CNCs) provide colloidal stability credit to electrostatic repulsion between the like-charged particles. The introduction of sodium counter cations on the sulfate groups enables drying of the CNC suspensions without irreversible aggregation. Less is known about the effect of other counter cations than sodium on extending the properties of the CNC particles. Here, we introduce the alkali metal counter cations, Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup>, Rb<sup>+</sup>, and Cs<sup>+</sup>, on sulfated CNCs without an ion exchange resin, which, so far, has been a common practice. We demonstrate that the facile ion exchange is an efficient method to exchange to any alkali metal cation of sulfate half esters, with exchange rates between 76 and 89%. The ability to form liquid crystalline order in rest was observed by the presence of birefringence patterns and followed the Hofmeister series prediction of a decreasing ability to form anisotropy with an increasing element number. However, we observed the K-CNC rheology and birefringence as a stand-out case within the series of alkali metal modifications, with dynamic moduli and loss tangent indicating a network disruptive effect compared to the other counter cations, whereas observation of the development of birefringence patterns in flow showed the absence of self- or dynamically-assembled liquid crystalline order.https://www.mdpi.com/2079-4991/12/18/3131cellulose nanocrystalsion exchangeion pairsrheologybirefringencerheo-PLI |
| spellingShingle | Patrick Petschacher Reza Ghanbari Carina Sampl Helmar Wiltsche Roland Kádár Stefan Spirk Tiina Nypelö Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations Nanomaterials cellulose nanocrystals ion exchange ion pairs rheology birefringence rheo-PLI |
| title | Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations |
| title_full | Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations |
| title_fullStr | Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations |
| title_full_unstemmed | Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations |
| title_short | Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations |
| title_sort | dynamic and static assembly of sulfated cellulose nanocrystals with alkali metal counter cations |
| topic | cellulose nanocrystals ion exchange ion pairs rheology birefringence rheo-PLI |
| url | https://www.mdpi.com/2079-4991/12/18/3131 |
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