Quantitative Calorimetric Studies of the Chiral Nematic Mesophase in Aqueous Cellulose Nanocrystal Suspensions

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2020-09-15

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Mcode

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Language

en

Pages

8
10830-10837

Series

Langmuir : the ACS journal of surfaces and colloids, Volume 36, issue 36

Abstract

Aqueous suspensions of cellulose nanocrystals (CNCs) can spontaneously form a chiral nematic mesophase at a critical concentration (c*). Unfortunately, no current analytical technique permits rapid detection of c*. Herein, we introduce a facile and accurate approach to assess c* rapidly (<2 h) from a small sample volume and compare our results with those obtained by conventional methods. Our strategy employs isothermal titration calorimetry (ITC) to measure the heat associated with interactions in the suspension, which can identify the onset of mesophase formation as the heat signature is sensitive to the suspension viscosity and thus capable of detecting small changes in the suspension environment. We measure c* for CNC samples differing in surface charge and aspect ratio, and find that both lower aspect ratios and higher surface charges increase c*. Our ITC results reveal the role of CNC interactions prior to the visual observation of mesophase formation and elucidate mesomorphic effects related to nanocrystals and their suspensions.

Description

| openaire: EC/H2020/788489/EU//BioELCell

Keywords

Materials Science(all), Condensed Matter Physics, Surfaces and Interfaces, Spectroscopy, Electrochemistry, 216 Materials engineering

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Citation

Facchine , E G , Jin , S A , Spontak , R J , Khan , S A & Rojas , O J 2020 , ' Quantitative Calorimetric Studies of the Chiral Nematic Mesophase in Aqueous Cellulose Nanocrystal Suspensions ' , Langmuir : the ACS journal of surfaces and colloids , vol. 36 , no. 36 , pp. 10830-10837 . https://doi.org/10.1021/acs.langmuir.0c01871