Functional Materials by Click Chemistry

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Functional Materials by Click Chemistry
Daugaard, Anders Egede
Publication date:
2009
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Citation (APA):
Daugaard, A. E. (2009). Functional Materials by Click Chemistry. Technical University of Denmark.

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Functional Materials by Click Chemistry
PhD thesis
Anders Egede Daugaard
2009
Functional Materials by Click
Chemistry
Danish Polymer Centre
Department of Chemical and Biochemical
Engineering
Technical University of Denmark
Kgs. Lyngby Denmark
Anders Egede Daugaard
February 2009
1
Copyright (cid:2)c Anders Egede Daugaard, 2009
ISBN-13: 978-87-92481-00-9
Printed by J&R Frydenberg A/S, Copenhagen, Denmark
2
Acknowledgement
This thesis is the result of my Ph.D. project carried out at the Danish Polymer
Centre (DPC) in Department of Chemical and Biochemical Engineering at the
Technical University of Denmark (DTU) from 2006 to 2009. The project was
financedinpartbyDTUandbytheDanishResearchCouncilforTechnologyand
Production Sciences through the frame work programme“Design and Processing
of Polymers for Microfluidic Applications”, grant 26-04-0074.
FirstandforemostIwouldliketothankmysupervisorProfessorSørenHvilsted
forgivingmetheopportunityofworkingonthisinterestingproject. Ihavealways
appreciatedyour support and guidance with the project allowing me to bring my
own ideas and to a large extent also to carry them out in the lab. Especially,
our sometimes too long meetings with discussions of new chemistry and other
approaches have been enjoyed tremendously on my behalf. I would also like to
thankyouforpushingmetogotoCaliforniawhenneededandforestablishingthe
contact to Professor Craig J. Hawker at University of California Santa Barbara
(UCSB) for my external research stay.
At UCSB I would like to thank Professor Craig J. Hawker for allowing me to
come to his group and experience the dynamic research environment supported
by his enthusiasm for science and research. It was a great pleasure working with
Ph.D.AnzarKhanbotheducationallyandonapersonallevel,youreallyincreased
thevalueofmystayatUCSB.AlsoPh.D.JosPaulusseisthankedforthehelpful
discussions and for supplying the cyclic monomers when time was getting tight
at the end. My lab mate Ph.D. student Denis Damiron from the University of
Lyon is thanked for many great times in Santa Barbara and his impressively
infectious good spirits. All the people from the Materials Research Department
are appreciated for contributing to my stay by being very welcoming and always
helpful with even the smallest of things. It was a very good experience sharing
the spring of 2008 with all of you in Santa Barbara, and I will always remember
it.
AtRisøDTUIwouldliketothankProfessorNielsB.Larsenforthediscussions
and collaboration in relation to the conductive polymers and for his help with
XPS analyses at almost all times of the day. It has been a great inspiration
working with you on this project. Also Ph.D. Thomas S. Hansen is thanked for
the collaboration on the conductive polymers and always contributing with new
ideas keeping things moving constantly.
From DTU nanotech I would like to thank AssociateProfessor OliverGeschke,
SeniorResearcherNoemiRozlosnikandPh.D.StudentJanKafkaforalltheirhelp
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with the electrochemical analyses.
I would also like to thank Kim Chi Szabo at DPC for her assistance with DSC
and SEC analyses. Associate Professor Katja Jankova for clarification of all the
smalldetailsandforhelponpolymerizations. Iwouldliketothankmyofficemates
Natanya M.L. Hansen, Anne Katrine K. Overgaard, Charlotte Juel Fristrup and
Irakli Javakhisvili for many discussions and for creating an inspiring and relaxed
atmosphere. All my other colleagues at DPC are also acknowledged for many
good experiences throughout the last three years.
FinallyIwouldalsoliketothankmyfriendsandfamilywhohavealwaysgiven
the helpful support whenever it was needed. A special thanks to my wife Anja
whohasbeenespeciallytolerantofmyirrationalbehaviorduringthelastmonths
of my thesis work.
Kgs. Lyngby, 26th of February 2009.
Anders Egede Daugaard
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Abstract
This thesis is based on the preparation of new functional materials through the
concept of click chemistry and especially by the use of the highly efficient copper
catalyzed cycloaddition of alkynes and azides (CuAAC).
Initially, carboxylic acid polymer surfaces have been prepared. These func-
tional polystyrenes have been synthesized through an approach based on poly(4-
hydroxystyrene), followed by a Williamson introduction of an alkyne and sub-
sequent cycloadditions. The approach has been applied to both commercially
available homo- and copolymers illustrating the broad range of possible applica-
tions. In addition to the commercial polymers, the free radical copolymerization
of 4-tert-butoxystyrene and styrene has been investigated for preparation of spe-
cific loadings. It was found that the copolymerization yields a perfectly random
copolymer with reactivity ratios close to one. The surface properties of the pre-
pared carboxylic acid polymers have been investigated using both X-ray photo-
electronspectroscopyandcontactanglemeasurementsonthinfilms. Theloading
offunctionalgroupsandminorstructuralchangeswerefoundtostronglyinfluence
the accessibility of carboxylic acids on the surface.
This approachhas also been appliedfor preparationof new monomersfor pho-
topolymer systems. The holographic systems investigated have been based on
macromonomers prepared through the traditional Frech´et type benzyl ethers as
well as on a new type of naphthalene end group functionalized dendrons build
through thiol-ene chemistry. Application of cycloadditions for preparation of
cyclic analogues were also investigated using two alkyne functional lactone acry-
lates. These were functionalized through cycloadditions with azides illustrating a
highly efficient way of introducing substituents into the cyclic monomers before
polymerization. The holographic characterizations of dendronized macromono-
mer photopolymer systems clearly showed that there was a beneficial effect of
the dendritic structure. This results in a lowering of the volume shrinkage of the
photopolymer system, while maintaining a high storage capacity.
Alsonovelconductivepolymersbasedonpoly(3,4-ethylenedioxythiophene)have
beenprepared. Anewazidefunctionalmonomerwassynthesizedandpolymerized,
enabling the introduction of new functionalities to the conductive polymer. The
CuAAC on the insoluble conductive polymer was optimized using a fluorescent
alkyne,findingoptimalconditionsof20hoursatroomtemperature. Additionally
conductive polymers with different surface properties were prepared through the
optimizedmethod. Experimentswithmicrowavereactionsperformedon the con-
ductive polymer, were found to reduce the reaction time considerably, resulting
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in reaction times on the order of minutes. In addition to this, it was found that
thereactioncouldbelocalizedselectivelyoneitherofapairofinterdigitatedelec-
trodesbyelectrochemicalreductionofthecatalyst. Finally,themodularityofthe
approach has been exploited in the preparation of new conductive polymers for
applications as micro sensors. Here receptors such as a 12-crown-4 ether, biotin
or ferrocene have been covalently linked to the surface. Initial investigations of
the sensing properties of these conductive polymers are presented.
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Resum´e
DennePh.D.afhandlingerbaseretp˚afremstillingenaffunktionellematerialerved
hjælp af konceptet click kemi. Specielt er de meget effektive kobber katalyserede
cykloadditioner mellem azider og alkyner (CuAAC) anvendt i flere tilfælde.
I den første del af projektet er der arbejdet med udvikling af nye polymer-
film med carboxylsyrer p˚a overfladen. Disse er fremstillet udfra funktionelle
polystyrener baseret p˚a poly(4-hydroxystyren). Poly(4-hydroxystyren) er ved en
Williamson ether syntese omdannet til den tilsvarende propargyl ether, der efter-
følgende er funktionaliseret igennem CuAAC med carboxylsyre azider. Denne
strategi er blevet anvendt p˚a b˚ade komercielle homo- og copolymerer illustre-
rende de brede anvendelsesmuligheder. Udover de komercielle prøver er ligeledes
fremstillingen af copolymerer af 4-tert-butoxystyren og styren blevet undersøgt
for at kunne variere mængden af de funktionelle grupper. I den forbindelse blev
reaktivitets forholdene undersøgt, og det kunne konstateres, at der ved copoly-
merisation at de to monomerer bliver produceret en random copolymer, da reak-
tivitetsforholdenevartætp˚aen. Kontaktvinkelm˚alingerogX-rayphotoelectron
spektroskopierblevetanvendttilundersøgelseafoverfladeegenskaberneforpoly-
merfilm fremstillet af de respektive copolymerer ved spincoating. Gennem disse
undersøgelser er det vist, at selv sm˚a strukturelle ændringer samt ændringer i
mængden af funktionelle grupper i copolymererne, har stor indflydelse p˚a mæng-
den af carboxylsyrer p˚a overfladen.
Ligeledes er denne tilgang til funktionalisering af makromolekyler anvendt ved
fremstilling af nye makromonomerer med henblik p˚a anvendelser i photopolymer
systemer til holografisk data opbevaring. De undersøgte makromonomerer har
b˚ade været baseret p˚a de velkendte Frech´et type benzyl ethere, samt p˚a en ny
naphthalenfunktionalisetdendronfremstilletvedthiol-enkemi. Sideløbendeblev
en anden strategi, rettet mod fremstilling af nye monomerer der polymeriserer
ved ring˚abning under fri radikal betingelser, undersøgt. Her blev forskellige cyk-
loadditioner anvendt til reaktion af cykliske alkyn funktionelle acrylater før poly-
merisation,identificeretsomeneffektivmetodetilfremstillingafnyemonomerer.
Karakterisering af de holografiske egenskaber for de forskellige systemer viste, at
de dendritiske makromonomerer resulterede i en minimal volumen ændring ved
polymerisation, hvor eksempler p˚a volumen ændringer helt ned til 0.01% blev
fundet uden en tilsvarende reduktion i lager kapaciteten.
Derudover er der udviklet en ny metode til funktionalisering af den ledende
polymerpoly(3,4-ethylenedioxythiophene)(PEDOT).Hererennyazidfunktionel
monomer fremstillet og polymeriseret til PEDOT-N , hvorefter funktionalisering
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ved CuAAC er optimeret. Optimeringen blev udført ved reaktion med en alkyn
funktionel fluorofor, hvorved en standard reaktionstid p˚a 20 timer blev fundet.
Ligeledes er metoden ogs˚a anvendt til fremstilling af ledende polymerfilm med
forskellige overflade egenskaber. Mikrobølgeovns reaktioner foretaget p˚a den azid
funktionelle ledende polymer viste, at denne teknik kunne anvendes til at opn˚a
en reduktion af reaktionstiden til nogle f˚a minutter. Ligeledes er selektiv funk-
tionaliseringaf mikro elektroder baseret p˚a PEDOT-N blevet undersøgt. I dette
3
tilfælde blev funktionalisering af to sammenflettede elektroder foretaget selektivt
ved elektrokemisk reduktion af katalysatoren p˚a hver af de to elektroder. Slut-
teligterdetmodulærekoncepticycloadditionerneudnyttettilfremstillingafnye
materialer med henblik p˚a anvendelser i mikro sensorer. Her er det lykkedes at
bindeen12-krone-4ether,biotinellerferrocenp˚aoverfladenafdenledendepoly-
mer. Indledende undersøgelserafdisseledendepolymerersegenskabersommikro
sensorer bliver her præsenteret.
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