% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Prause:1018701,
      author       = {Prause, Albert},
      title        = {{S}tructural {I}nvestigation of {H}ydrophobically
                      {M}odified {T}hermoresponsive {P}olymers and{T}heir
                      {I}nfluence on the {R}heology of {M}icroemulsions},
      school       = {TU Berlin},
      type         = {Dissertation},
      reportid     = {FZJ-2023-04995},
      pages        = {182p},
      year         = {2023},
      note         = {Dissertation, TU Berlin, 2023},
      abstract     = {A library of nonsymmetrical thermosensitive BAB* block
                      copolymers was investigated in terms of their aggregation
                      behavior and rheological properties as a function of
                      temperature in aqueous solutions. Additionally, these block
                      copolymers were used to study the modification of
                      temperature-dependent rheological properties of
                      microemulsions. The block copolymers comprise a permanently
                      hydrophilic poly(N,N -dimethylacrylamide) (pDMAm) block
                      “A”, a permanently hydrophobic n-dodecyl (C12) chain as
                      end-group “B”, and a ther-moresponsive (TR) block
                      “B*” featuring a lower critical solution temperature
                      (LCST). To vary the chemical nature and LCST behavior,
                      different polyacrylamides, i. e., poly(N
                      -n-propylacrylamide) (pNPAm), poly(N,N -diethylacrylamide)
                      (pDEAm), poly(N -isopropyl-acrylamide) (pNiPAm), and poly(N
                      -acryloylpyrrolidine) (pNAP), were introduced as TR blocks.
                      Additionally, the length of the TR block was varied
                      systematically as well as the architecture of the block
                      copolymer, for which three types were employed, i. e., BAB*,
                      B2AB*, and B(AB*)2.The influence of the length of the TR
                      block on the aggregation behavior and temperature response
                      was studied via light and neutron scattering (SLS, DLS, and
                      SANS). For TR blocks with more than 40 monomer units, a
                      marked hydrophobic interaction occurs above the LCST,
                      leading to ordered, well-structured clusters of micellar
                      aggregates. Thus, the temperature-dependent mesoscopic
                      organization of aggregates can be tuned by the length and
                      type of the TR block.The temperature response of rheological
                      properties was investigated and compared for the various
                      copolymer architectures. Depending on the TR block and the
                      copolymer archi-tecture, their solution’s viscosity can
                      increase significantly with rising temperature. These
                      results are well in line with the observed mesoscopic
                      organization obtained by SLS, DLS, and SANS experiments.
                      Additionally, fluorescence experiments using the
                      solvatochromic probe Prodan revealed a direct relationship
                      between the increased viscosity and the for-mation of
                      additional hydrophobic domains of TR blocks. Consequently,
                      the viscoelastic properties of aqueous solutions can be
                      tuned temperature dependently by carefully designing these
                      copolymers.Following this, the viscoelastic properties of
                      low-viscous oil-in-water (O/W) microemul-sions (MEs) can
                      also be adjusted. For a properly chosen ME concentration,
                      these block copolymers lead to a viscosity increase with
                      rising temperature. At a polymer concentration of about 22 g
                      L−1, the most pronounced enhancement was observed for the
                      pNPAm-based systems, with factors up to about 3, 5, and 8
                      for BAB*, B2AB*, and B(AB*)2, respectively. The enhancement
                      is caused by the formation of a transient net-work mediated
                      by TR blocks, as evidenced by the direct correlation between
                      the viscosity enhancement and the attraction strength. This
                      kind of tailored temperature-dependent viscosity control of
                      surfactant-based systems could therefore be advantageous for
                      applications requiring a high hydrophobic payload, which is
                      accomplished by the droplet microemulsion.},
      cin          = {JCNS-FRM-II / MLZ},
      cid          = {I:(DE-Juel1)JCNS-FRM-II-20110218 / I:(DE-588b)4597118-3},
      pnm          = {6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ)
                      (POF4-6G4)},
      pid          = {G:(DE-HGF)POF4-6G4},
      experiment   = {EXP:(DE-MLZ)KWS1-20140101},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.34734/FZJ-2023-04995},
      url          = {https://juser.fz-juelich.de/record/1018701},
}