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Preparation of electrically conducting cellulose fibres utilizing polyelectrolyte multilayers of poly(3,4-ethylenedioxythiophene): poly(styrene sulphonate) and poly(allyl amine)
STFI-Packforsk AB.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0001-8622-0386
2007 (English)In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 43, no 10, 4075-4091 p.Article, review/survey (Refereed) Published
Abstract [en]

The primary goal with this work is to create electrically conductive cellulose fibres, this has been done to explore possible new applications for fibre based material. This research uses various methods to create polyelectrolyte multilayers (PEMs) on bleached softwood fibres and on SiO2 model surfaces, by sequentially treating these materials with poly(3,4ethylenedioxythiophene):poly(styrene sulphonate) (PEDOT:PSS) and poly(allyl amine) (PAH). Paper sheets were then produced from the PEM-modified pulp and evaluated in terms of tensile strength, adsorbed amount of polymer, and electrical conductivity. To evaluate the influence of fibre charge on the measured paper properties, pulps of two different initial fibre charge densities were prepared via carboxymethylation. Because of the bluish colour of PEDOT:PSS, the build-up of PEM could be easily followed, since the fibres grew increasingly darker blue throughout the modification sequence. The conductivity of the fibre network increased by 2-3 orders of magnitude when the pulp of a higher fibre charge density was used. This suggests that it is more important to create a fibrous network with a high fibre-fibre joint strength and a large total joined area in the sheet rather than to maximize the adsorbed amount of PEDOT:PSS. A difference in conductivity could also be noted depending on the polyelectrolyte adsorbed in the outer layer, PAH lowered the conductivity compared to PEDOT:PSS. Evaluating the mechanical properties revealed that the use of PEDOT:PSS reduces the tensile strength of the paper. When five double layers had been adsorbed onto the carboxymethylated sample in which PEDOT:PSS formed the outer layer, calculations indicated a 25% decrease in tensile strength compared to that of reference material without PEMs. ESEM studies indicate that PEM treatment produces a significantly changed and somewhat smoother fibre surface.

Place, publisher, year, edition, pages
2007. Vol. 43, no 10, 4075-4091 p.
Keyword [en]
electrical, conductive, polymer, polyelectrolyte, multilayer, mechanical properties, wood pulp fibers, paper strength, wettability, polymer, polyacetylene, derivatives, adsorption, joint, angle
National Category
Paper, Pulp and Fiber Technology
URN: urn:nbn:se:kth:diva-17065DOI: 10.1016/j.eurpolymj.2007.03.053ISI: 000250386600002ScopusID: 2-s2.0-34848827911OAI: diva2:335108
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2010-08-23Bibliographically approved
In thesis
1. On the Adhesion Between Substrates Covered with Polyelectrolyte Multilayers
Open this publication in new window or tab >>On the Adhesion Between Substrates Covered with Polyelectrolyte Multilayers
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This thesis examines the formation of Polyelectrolyte Multilayers (PEM) on cellulose fibres as a new way of influencing the fibre surface and the adhesion between wood fibres. The aim of the study was to enhance the fundamental understanding of the adsorption mechanisms behind the formation of Polyelectrolyte Multilayers on cellulose fibres; to study how the properties of the layers can be influenced and to show how the properties of the layers influence the adhesion between the fibres and the strength of paper sheets made from the PEM treated fibres.

Different polyelectrolyte systems are known to form PEMs with different properties, and in this work two different polymer systems were extensively studied: poly(dimethyldiallylammonium chloride) (PDADMAC) / poly(styrene sulphonate) (PSS), which are both strong polylectrolytes (i.e. are highly charged over a wide range of pH) and poly allylaminehydrochloride (PAH) /poly acrylic acid (PAA), which are both weak polyelectorlytes (i.e. sensitive to pH changes). PEMs were also formed from PAH/ poly(3,4-ethylenedioxythiophene):PSS (PEDOT:PSS), in order to form electrically conducting PEMs on fibres and PEM-like structures were formed from polyethylene oxide (PEO) and polyacrylic acid (PAA).

In order to study the influence of the PEM on adhesion and paper strength, fibres were treated and used to form sheets which were physically tested according to determine the tensile index and strain at break. Both these systems were studied using different molecular mass fractions. High molecular mass PDADMAC/PSS (>500k/1000k) had a significantly greater influence as a function of the number of layers than low molecular mass PDADMAC/PSS (30k/80k). In contrast, sheets made from high molecular mass PAH/PAA (70k/240k) showed a significantly lower increase in strength than sheets made from low molecular PAH/PAA investigated earlier. Both these systems had a greater influence on paper strength when the cationic polyelectrolyte was adsorbed in the outermost layer. The amount of polyelectrolytes adsorbed on the fibres was determined using polylectrolyte titration (PET) and destructive analytical methods. Adsorption to model surfaces of silicon oxide was studied before the adsorption on fibres, in order to understand the influence on PEM properties of parameters such as salt concentration and adsorption time.

Adhesion studies of surfaces coated with PAH/PAA using AFM, showed an increase in adhesion as a function of the number of adsorbed layers. The adhesion was higher when PAH was adsorbed in the outermost layers. Individual fibres were also partly treated using a Dynamic Contact Angle analyser (DCA) and were studied with regard to their wettability. In general, the wettability was lower when the cationic polymer was outermost. The level of adhesion and paper strength are discussed in terms of rigidity and wettability and the PEMs demonstrating a large number of free chain ends, a large chain mobility and a low wettability was found to have the greatest influence to adhesion and paper strength.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. viii, 60 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2008:27
fibre, polyelectorlyte, multilayer, wettability, contact angle, paper strength, atomic force microscopy, surface force apparatus
National Category
Paper, Pulp and Fiber Technology
urn:nbn:se:kth:diva-4825 (URN)978-91-7178-955-6 (ISBN)
Public defence
2008-05-16, F3, Flodissalen, Lindstedtsvägen 26, Stockholm, 10:00
QC 20100823Available from: 2008-06-13 Created: 2008-06-13 Last updated: 2010-08-23Bibliographically approved

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