@article{KyriakosAravopoulouAugsbachetal.2014,
  author    = {Kyriakos, Konstantinos and Aravopoulou, Dionysia and Augsbach, Lukas and Sapper, Josef and Ottinger, Sarah and Psylla, Christina and Rafat, Ali Aghebat and Benitez-Montoya, Carlos Adrian and Miasnikova, Anna and Di, Zhenyu and Laschewsky, Andr{\´e} and M{\"u}ller-Buschbaum, Peter and Kyritsis, Apostolos and Papadakis, Christine M.},
  title     = {Novel thermoresponsive block copolymers having different architectures-structural, rheological, thermal, and dielectric investigations},
  series = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  volume    = {292},
  journal   = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  number    = {8},
  publisher = {Springer},
  address   = {New York},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-014-3282-0},
  pages     = {1757 -- 1774},
  year      = {2014},
  abstract  = {Thermoresponsive block copolymers comprising long, hydrophilic, nonionic poly(methoxy diethylene glycol acrylate) (PMDEGA) blocks and short hydrophobic polystyrene (PS) blocks are investigated in aqueous solution. Various architectures, namely diblock, triblock, and starblock copolymers are studied as well as a PMDEGA homopolymer as reference, over a wide concentration range. For specific characterization methods, polymers were labeled, either by partial deuteration (for neutron scattering studies) or by fluorophores. Using fluorescence correlation spectroscopy, critical micellization concentrations are identified and the hydrodynamic radii of the micelles, r (h) (mic) , are determined. Using dynamic light scattering, the behavior of r (h) (mic) in dependence on temperature and the cloud points are measured. Small-angle neutron scattering enabled the detailed structural investigation of the micelles and their aggregates below and above the cloud point. Viscosity measurements are carried out to determine the activation energies in dependence on the molecular architecture. Differential scanning calorimetry at high polymer concentration reveals the glass transition of the polymers, the fraction of uncrystallized water and effects of the phase transition at the cloud point. Dielectric relaxation spectroscopy shows that the polarization changes reversibly at the cloud point, which reflects the formation of large aggregates upon heating through the cloud point and their redissolution upon cooling.},
  language  = {en}
}
@article{KyriakosPhilippAdelsbergeretal.2014,
  author    = {Kyriakos, Konstantinos and Philipp, Martine and Adelsberger, Joseph and Jaksch, Sebastian and Berezkin, Anatoly V. and Lugo, Dersy M. and Richtering, Walter and Grillo, Isabelle and Miasnikova, Anna and Laschewsky, Andr{\´e} and M{\"u}ller-Buschbaum, Peter and Papadakis, Christine M.},
  title     = {Cononsolvency of water/methanol mixtures for PNIPAM and PS-b-PNIPAM: pathway of aggregate formation investigated using time-resolved SANS},
  series = {Macromolecules : a publication of the American Chemical Society},
  volume    = {47},
  journal   = {Macromolecules : a publication of the American Chemical Society},
  number    = {19},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0024-9297},
  doi       = {10.1021/ma501434e},
  pages     = {6867 -- 6879},
  year      = {2014},
  abstract  = {We investigate the cononsolvency effect of poly(N-isopropylacrylamide) (PNIPAM) in mixtures of water and methanol. Two systems are studied: micellar solutions of polystyrene-b-poly(N-isopropylacrylamide) (PS-b-PNIPAM) diblock copolymers and, as a reference, solutions of PNIPAM homopolymers, both at a concentration of 20 mg/mL in DO. Using a stopped-flow instrument, fully deuterated methanol was rapidly added to these solutions at volume fractions between 10 and 20\%. Time-resolved turbidimetry revealed aggregate formation within 10-100 s. The structural changes on mesoscopic length scales were followed by time-resolved small-angle neutron scattering (TR-SANS) with a time resolution of 0.1 s. In both systems, the pathway of the aggregation depends on the content of deuterated methanol; however, it is fundamentally different for homopolymer and diblock copolymer solutions: In the former, very large aggregates (>150 nm) are formed within the dead time of the setup, gradient appears at their surface in the late stages. In contrast, the growth of the aggregates in the latter system features different regimes, and the final aggregate size is 50 nm, thus much smaller than for the homopolymer. For the diblock copolymer, the time dependence of the aggregate radius can be described by two models: In the initial stage, the diffusion-limited coalescence model describes the data well; however, the resulting coalescence time is unreasonably high. In the late stage, a logarithmic coalescence model based on an energy barrier which is proportional to the aggregate radius is successfully applied. and a concentration},
  language  = {en}
}