Dynamic and Static Assembly of Sulfated Cellulose Nanocrystals with Alkali Metal Counter Cations
Journal article, 2022

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+, Na+, K+, Rb+, and Cs+, 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.

rheo-PLI

cellulose nanocrystals

rheology

ion exchange

ion pairs

birefringence

Author

P. Petschacher

Technische Universität Graz

Reza Ghanbari

Chalmers, Industrial and Materials Science, Engineering Materials

C. Sampl

Technische Universität Graz

H. Wiltsche

Technische Universität Graz

Roland Kádár

Chalmers, Industrial and Materials Science, Engineering Materials

Stefan Spirk

Tiina Nypelö

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Nanomaterials

20794991 (eISSN)

Vol. 12 3131

Development of a new rheometer system at MAX IV

The Chalmers University Foundation, 2019-03-01 -- 2021-12-31.

MAX IV Laboratory, 2019-03-01 -- 2021-12-31.

Advanced rheometry of CNC based systems

Wallenberg Wood Science Center (WWSC), 2019-01-01 -- 2024-12-31.

Subject Categories

Other Mechanical Engineering

Paper, Pulp and Fiber Technology

Infrastructure

Chalmers Materials Analysis Laboratory

Areas of Advance

Materials Science

DOI

10.3390/nano12183131

More information

Latest update

1/3/2024 9