Smart magnetic dispersions - from switchable release to well-defined hybrid nanofibers

dc.contributor.authorBannwarth, Markus
dc.date.accessioned2014-02-06T14:06:16Z
dc.date.available2014-02-06T15:06:16Z
dc.date.issued2014
dc.description.abstractThe synthesis, characterization and application of aqueous dispersions of superparamagnetic/polymer hybrid nanoparticles and capsules is described. Implementation of the superparamagnetic moiety into the polymer matrix enables a response of the nanomaterials towards an external magnetic field. Application of the external field is used for two main purposes: i) As heat generator, when an alternating magnetic field is applied. ii) As structuring agent to self-assemble superparamagnetic nanoparticles in the external field.rnIn the first part, superparamagnetic nanoparticles were used as heat generators in order to achieve a magnetic field induced release of an active compound from nanocontainers. To achieve such a release in remote-controlled fashion, the encapsulation of superparamagnetic nanoparticles into polymer nanocapsules was combined with the integration of a thermolabile compound into the shell of the nanocontainers. The magnetic nanoparticles acted as generators for heat, which decomposed the thermolabile compound. Pores were created in the degrading shell and an active substance was released.rn Additionally, the self-assembly of polymer nanoparticles, which were labeled with a superparamagnetic moiety as structuring agent, could be demonstrated. A combination of a magnetic field induced self-assembly and a sintering of neighboring particles upon an increase in temperature above the glass transition temperature of the polymer was used to form stable architectures. Various structures with tunable periodicity could be obtained ranging from smooth linear nanofibers to zigzag fibers. Besides solely creating linear architectures, the frugal process additionally allowed the creation of arrangements in analogy to more complex polymer architectures: By the introduction of defined junction points, the generation of branched structures and networks was demonstrated. Additionally, by tailoring the interaction of differently sized particles, the preparation of nanoparticle arrangements in statistical or block copolymer fashion was shown. Moreover, a reversible linear assembly and linkage of the nanoparticles was demonstrated following a lock/unlock mechanism. Therefore, the particles were locked in their linear assembly by a stable iron(III) hydroxamato-complex and unlocked by addition of a reducing agent and formation of a less stable iron(II)-complex.Further, in various projects with collaboration partners, nanoparticles and nanocapsules were labeled with a superparamagnetic moiety for their use as contrast agents in magnetic resonance imaging or as magnetically separable dispersions.en_GB
dc.identifier.doihttp://doi.org/10.25358/openscience-3685
dc.identifier.urihttps://openscience.ub.uni-mainz.de/handle/20.500.12030/3687
dc.identifier.urnurn:nbn:de:hebis:77-36500
dc.language.isoeng
dc.rightsInC-1.0de_DE
dc.rights.urihttps://rightsstatements.org/vocab/InC/1.0/
dc.subject.ddc540 Chemiede_DE
dc.subject.ddc540 Chemistry and allied sciencesen_GB
dc.titleSmart magnetic dispersions - from switchable release to well-defined hybrid nanofibersen_GB
dc.typeDissertationde_DE
jgu.description.extent193 S.
jgu.organisation.departmentExterne Einrichtungen
jgu.organisation.nameJohannes Gutenberg-Universität Mainz
jgu.organisation.number0000
jgu.organisation.placeMainz
jgu.organisation.rorhttps://ror.org/023b0x485
jgu.organisation.year2014
jgu.rights.accessrightsopenAccess
jgu.subject.ddccode540
jgu.type.dinitypePhDThesis
jgu.type.resourceText
jgu.type.versionOriginal worken_GB
opus.date.accessioned2014-02-06T14:06:16Z
opus.date.available2014-02-06T15:06:16
opus.date.modified2020-06-17T09:55:53Z
opus.identifier.opusid3650
opus.institute.number5060
opus.metadataonlyfalse
opus.organisation.stringExterne Einrichtungen: Max-Plank-Institut für Polymerforschungde_DE
opus.subject.dfgcode00-000
opus.type.contenttypeDissertationde_DE
opus.type.contenttypeDissertationen_GB

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