Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Macro-, Micro- and Nanospheres from Cellulose: Their Preparation, Characterization and Utilization
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.ORCID iD: 0000-0002-4511-1076
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The structure of a polymeric material has a great influence in many fundamental scientific areas as well as in more applied science, since it affects the diffusion, permeability, mechanical strength, elasticity, and colloidal properties of the materials. The results in this thesis demonstrate that it is possible to fabricate solid and hollow cellulose spheres with a cellulose shell and encapsulated gas, liquid or solid particles and with a sphere size ranging from a few hundreds of nanometres to several millimetres, all with a tailored design and purpose.

The sizes of the different spheres have been controlled by three different preparation methods: large cellulose macrospheres by a solution solidification procedure, hollow micrometre-sized cellulose spheres by a liquid flow-focusing technique in microchannels, and nanometre-sized cellulose spheres by a membrane emulsification technique. 

The spheres were then modified in different ways in order to functionalize them into more advanced materials. This thesis demonstrates how to control the cellulose sphere dimensions and the wall-to-void volume ratio, the elasticity and the functionality of the spheres as such, where they were prepared to be pH-responsive, surface specific and X-ray active. These modifications are interesting in several different types of final materials such as packaging materials, drug release devices or advanced in vivo diagnostic applications.

In the more fundamental science approach, surface-smooth solid cellulose spheres were prepared for characterization of the macroscopic work of adhesion when a cellulose surface is separated from another material. Using these ultra-smooth macroscopic cellulose probes, it is possible to measure the compatibility and the surface interactions between cellulose and other materials which provide an important tool for incorporating cellulose into different composite materials. 

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. , 67 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2014:32
Keyword [en]
Cellulose, sphere, capsule, functionalization
National Category
Polymer Technologies
Research subject
Fibre and Polymer Science
Identifiers
URN: urn:nbn:se:kth:diva-149807ISBN: 978-91-7595-231-4 (print)OAI: oai:DiVA.org:kth-149807DiVA: diva2:741307
Public defence
2014-09-26, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20140829

Available from: 2014-08-29 Created: 2014-08-27 Last updated: 2014-08-29Bibliographically approved
List of papers
1. Hollow cellulose capsules from CO2 saturated cellulose solutions - Their preparation and characterization
Open this publication in new window or tab >>Hollow cellulose capsules from CO2 saturated cellulose solutions - Their preparation and characterization
Show others...
2013 (English)In: RSC Advances, ISSN 2046-2069, Vol. 3, no 7, 2462-2469 p.Article in journal (Refereed) Published
Abstract [en]

A new material consisting of mm-sized hollow cellulose spheres, for biomedical applications or for the preparation of low weight porous materials has been prepared by a unique solution precipitation (SP) method. The technique is based on three separate steps. In the first step, high molecular mass, non-modified cellulose is dissolved in a suitable solvent. This cellulose solution is then saturated with a suitable gas (CO2 or N2 in the present work) and finally this gas-saturated solution is drop-wise added to a water reservoir. In this step, the cellulose is precipitated and a gas bubble is nucleated in the center of the cellulose sphere. When stored in water, the hollow center is filled with water, indicating that the capsule wall is porous in nature. This was also supported by BET-area measurements as well as by high resolution SEM-images of broken capsule walls. The internal void volume of a capsule was about 5 μl and the wall volume was about 8 μl. It was also established that the properties of the cellulose capsules, i.e. wall and void volume, the specific surface area, the average pore size of the capsule wall, the wall density, and the compressive load capacity could be tuned by the choice of cellulose concentration in the solution before precipitation. The capsule wall volume and void volume were also affected by the choice of gas, the gas pressure and the gas dissolution time during the gas saturation step. The response of the cellulose wall of the prepared capsules to changes in pH and ion concentration in the surrounding solution was also investigated. The swelling-shrinking behavior was further investigated by introducing more charges to the capsule wall, via carboxymethylation of the cellulose. This was achieved by using carboxymethylated cellulose which increased the swelling-shrinking effect. The results show a typical polyelectrolyte gel behavior of the capsule wall and the wet modulus of the cellulose wall was determined to be between 0.09-0.2 MPa depending on the charge of the cellulose in the capsule wall. Furthermore, the freeze dried cellulose spheres had a modulus of 1.9-7.4 MPa, depending on the cellulose concentration during the preparation of the spheres. These cellulose capsules are suitable both for the preparation of porous materials, where these larger spheres are joined together in 3D-shaped materials, and for controlled release where the interior of the capsules is filled with active substances and these substances are released by controlling the pores in the capsule walls.

Keyword
Active substance, Biomedical applications, Carboxymethylation, Cellulose solutions, Compressive loads, Controlled release, Gas bubble, Gas dissolution, Gas pressures, Gas saturations, Gel behavior, High molecular mass, High resolution, Internal voids, Ion concentrations, Solution precipitation, Void volume, Wall density
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-118295 (URN)10.1039/c2ra22020b (DOI)000313812400052 ()2-s2.0-84872707086 (Scopus ID)
Note

QC 20130215

Available from: 2013-02-15 Created: 2013-02-14 Last updated: 2014-08-29Bibliographically approved
2. Lightweight, Highly Compressible, Noncrystalline Cellulose Capsules
Open this publication in new window or tab >>Lightweight, Highly Compressible, Noncrystalline Cellulose Capsules
2014 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 26, 7635-7644 p.Article in journal (Refereed) Published
Abstract [en]

We demonstrate how to prepare extraordinarily deformable, gas-filled, spherical capsules from nonmodified cellulose. These capsules have a low nominal density, ranging from 7.6 to 14.2 kg/m(3), and can be deformed elastically to 70% deformation at 50% relative humidity. No compressive strain-at-break could be detected for these dry cellulose capsules, since they did not rupture even when compressed into a disk with pockets of highly compressed air. A quantitative constitutive model for the large deformation compression of these capsules is derived, including their high-frequency mechanical response and their low-frequency force relaxation, where the latter is governed by the gas barrier properties of the dry capsule. Mechanical testing corroborated these models with good accuracy. Force relaxation measurements at a constant compression rendered an estimate for the gas permeability of air through the capsule wall, calculated to 0.4 mL mu m/m(2) days kPa at 50% relative humidity. These properties taken together open up a large application area for the capsules, and they could most likely be used for applications in compressible, lightweight materials and also constitute excellent model materials for adsorption and adhesion studies.

Keyword
Stability, Microbubbles, Dissolution, Behavior, Shells, Foams
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-148607 (URN)10.1021/la501118b (DOI)000338806500003 ()2-s2.0-84903974299 (Scopus ID)
Note

QC 20140812

Available from: 2014-08-12 Created: 2014-08-11 Last updated: 2017-12-05Bibliographically approved
3. Nanometer Smmoth, Macroscopic Spherical Cellulose Probes for Contact Adhesion Measurements
Open this publication in new window or tab >>Nanometer Smmoth, Macroscopic Spherical Cellulose Probes for Contact Adhesion Measurements
(English)Manuscript (preprint) (Other academic)
Identifiers
urn:nbn:se:kth:diva-150102 (URN)
Note

QS 2014

Available from: 2014-08-29 Created: 2014-08-29 Last updated: 2014-08-29Bibliographically approved
4. Native and functionalized micrometre-sized cellulose capsules prepared by microfluidic flow focusing
Open this publication in new window or tab >>Native and functionalized micrometre-sized cellulose capsules prepared by microfluidic flow focusing
Show others...
2014 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 37, 19061-19067 p.Article in journal (Refereed) Published
Abstract [en]

Cellulose capsules with average outer and inner radii of approximately 44 mu m and 29 mm respectively were prepared from cellulose dissolved in a mixture of lithium chloride and dimethylacetamide using a microfluidic flow focusing device (MFFD). The MFFD had three inlets where octane oil in a cellulose solution in silicone oil was used to produce a double emulsion containing a cellulose capsule. This technique enables the formation of capsules with a narrow size distribution which can be beneficial for drug delivery or controlled release capsules. In this respect, cellulose is a highly interesting material since it is known to cause no autoimmune reactions when used in contact with human tissue. Furthermore, by controlling the chemical properties of the cellulose, it is possible to trigger a swelling of the capsules and consequentially the release of an encapsulated substance, e. g. a model drug, when the capsule becomes exposed to an external stimulus. To demonstrate this, capsules were functionalized by carboxymethylation to be pH- responsive and to expand approximately 10% when subjected to a change in pH from 3 to 10. The diffusion constant of a model drug, a 4 kDa fluorescently labelled dextran, through the native capsule wall was estimated to be 6.5 X 10(-14) m(2) s(-1) by fitting fluorescence intensity data to Fick's second law.

Keyword
Liquid-Liquid Systems, Drop Formation, Poly(Dimethylsiloxane), Polyelectrolytes, Biocompatibility, Microspheres, Hydrogels, Delivery, Devices, Chip
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-146161 (URN)10.1039/c3ra47803c (DOI)000335559100001 ()2-s2.0-84899855931 (Scopus ID)
Funder
Science for Life Laboratory - a national resource center for high-throughput molecular bioscience
Note

QC 20140609

Available from: 2014-06-09 Created: 2014-06-09 Last updated: 2017-12-05Bibliographically approved
5. Immunoselective cellulose nanospheres: a versatile platform for nanotheranostics
Open this publication in new window or tab >>Immunoselective cellulose nanospheres: a versatile platform for nanotheranostics
2014 (English)In: ACS Macro Letters, E-ISSN 2161-1653, Vol. 3, no 11, 1117-1120 p.Article in journal (Refereed) Published
Abstract [en]

This paper describes a novel route for the preparation and functionalization of perfectly spherical cellulose nanospheres (CNSs), ranging from 100 to 400 nrn with a typical diameter of 160-170 nrn,for use in theranostics. The method of preparation enables both surface and interior bulk functionalization, and this presumably also makes the CNSs suitable for use in end-use applications other than theranostics. Surface functionalization was here demonstrated by antibody conjugation with an antibody specific toward the epidermal growth factor receptor (EGFR) protein, i.e., facilitating interaction with cancer cells having the EGFR. Besides showing specificity, the CNS-antibody conjugates showed a very low nonspecific binding. The CNSs could easily be bulk functionalized by embedding gold nanoparticles in the cellulose sphere matrix during CNS preparation to provide imaging contrast for diagnostic purposes.

National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-150104 (URN)10.1021/mz500507k (DOI)000345264800004 ()2-s2.0-84910641012 (Scopus ID)
Note

QC 20150115

Available from: 2014-08-29 Created: 2014-08-29 Last updated: 2017-12-05Bibliographically approved

Open Access in DiVA

Thesis(2340 kB)534 downloads
File information
File name FULLTEXT01.pdfFile size 2340 kBChecksum SHA-512
d8252ad46150d00c66d96d0e6888546470f3d7b86750f6b7419ae917cb775731a832447c82caa6589daca49ddd63b3c7d515e27139d0910224b8c4ac9b5edb7e
Type fulltextMimetype application/pdf

Authority records BETA

Carrick, Christopher

Search in DiVA

By author/editor
Carrick, Christopher
By organisation
Fibre Technology
Polymer Technologies

Search outside of DiVA

GoogleGoogle Scholar
Total: 534 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 424 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf