@article{HarmsRaetzkeFaupeletal.2010,
  author    = {Harms, Stephan and Raetzke, Klaus and Faupel, Franz and Egger, Werner and Ravello, Lori Boyd de and Laschewsky, Andr{\´e} and Wang, Weinan and M{\"u}ller-Buschbaum, Peter},
  title     = {Free volume and swelling in thin films of poly(n-isopropylacrylamide) end-capped with n-butyltrithiocarbonate},
  issn      = {1022-1336},
  doi       = {10.1002/marc.201000067},
  year      = {2010},
  abstract  = {The free volume in thin films of poly(N-isopropylacrylamid) end-capped with n-butyltrio-carbonate (nbc-PNIPAM) is probed with positron annihilation lifetime spectroscopy (PALS). The PALS measurements are performed as function of energy to obtain depth profiles of the free volume of nbc-PNIPAM films. The range of nbc-PNIPAM films with thicknesses from 40 to 200 nm is focused. With decreasing film thickness the free volume increases in good agreement with an increase in the maximum swelling capability of the nbc-PNIPAM films. Thus in thin hydrogel films the sorption and swelling behavior is governed by free volume.},
  language  = {en}
}
@article{BivigouKoumbaGoernitzLaschewskyetal.2010,
  author    = {Bivigou Koumba, Achille Mayelle and Goernitz, Eckhard and Laschewsky, Andr{\´e} and M{\"u}ller-Buschbaum, Peter and Papadakis, Christine M.},
  title     = {Thermoresponsive amphiphilic symmetrical triblock copolymers with a hydrophilic middle block made of poly(N- isopropylacrylamide) : synthesis, self-organization, and hydrogel formation},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-009-2179-9},
  year      = {2010},
  abstract  = {Several series of symmetrical triblock copolymers were synthesized by the reversible addition fragmentation chain transfer method. They consist of a long block of poly(N-isopropylacrylamide) as hydrophilic, thermoresponsive middle block, which is end-capped by two small strongly hydrophobic blocks made from five different vinyl polymers. The association of the amphiphilic polymers was studied in dilute and concentrated aqueous solution. The polymer micelles found at low concentrations form hydrogels at high concentrations, typically above 30-35 wt.\%. Hydrogel formation and the thermosensitive rheological behavior were studied exemplarily for copolymers with hydrophobic blocks of polystyrene, poly(2-ethylhexyl acrylate), and poly(n-octadecyl acrylate). All systems exhibited a cloud point around 30 A degrees C. Heating beyond the cloud point initially favors hydrogel formation but continued heating results in macroscopic phase separation. The rheological behavior suggests that the copolymers associate into flower-like micelles, with only a small share of polymers that bridge the micelles and act as physical cross-linkers, even at high concentrations.},
  language  = {en}
}
@article{AdelsbergerKulkarniJainetal.2010,
  author    = {Adelsberger, Joseph and Kulkarni, Amit and Jain, Abhinav and Wang, Weinan and Bivigou Koumba, Achille Mayelle and Busch, Peter and Pipich, Vitaliy and Holderer, Olaf and Hellweg, Thomas and Laschewsky, Andr{\´e} and M{\"u}ller-Buschbaum, Peter and Papadakis, Christine M.},
  title     = {Thermoresponsive PS-b-PNIPAM-b-PS micelles : aggregation behavior, segmental dynamics, and thermal response},
  issn      = {0024-9297},
  doi       = {10.1021/Ma902714p},
  year      = {2010},
  abstract  = {We have studied I lie thermal behavior of amphiphilic, symmetric triblock copolymers having short, deuterated polystyrene (PS) end blocks and a large poly(N-isopropylacrylarnicle) (PNIPAM) middle block exhibiting a lower critical solution temperature (LCST) in aqueous solution. A wide range of concentrations (0.1-300 mg/mL) is investigated using it number of analytical methods such as fluorescence correlation spectroscopy (FCS), turbidimetry, dynamic light scattering (DLS), small-angle neutron scattering (SANS), and neutron spin-echo spectroscopy (NSE). The critical micelle concentration is determined using FCS to be 1 mu M or less. The collapse of the micelles at the LCST is investigated using turbidimetry and DLS and shows a weak dependence on the degree of polymerization of the PNIPAM block. SANS with contrast matching allows its to reveal the core-shell Structure of the micelles as well as their correlation as a function of temperature. The segmental dynamics of the PNIPAM shell are studied as a function of temperature and arc found to be faster in the collapsed state than in the swollen state. The mode detected has a linear dispersion in q(2) and is found to be faster in the collapsed state as compared to the swollen state. We attribute this result to the averaging over mobile and immobilized segments.},
  language  = {en}
}
@article{WangKaunePerlichetal.2010,
  author    = {Wang, Weijia and Kaune, Gunar and Perlich, Jan and Paradakis, Christine M. and Bivigou Koumba, Achille Mayelle and Laschewsky, Andr{\´e} and Schlage, K. and R{\"o}hlsberger, Ralf and Roth, Stephan V. and Cubitt, Robert and M{\"u}ller-Buschbaum, Peter},
  title     = {Swelling and switching kinetics of gold coated end-capped poly(N-isopropylacrylamide) thin films},
  issn      = {0024-9297},
  doi       = {10.1021/Ma902637a},
  year      = {2010},
  abstract  = {Thin thermoresponsive hydrogel films of poly(N-isopropylacrylamide) end-capped with n-butyltrithiocarbonate(nbc- PNIPAM) oil si I icon supports with a gold layer on top, causing an asymmetric confinement, are investigated. For two different gold layer thicknesses (nominally 0.4 and 5 rim), the swelling and switching kinetics are probed with in situ neutron reflectivity. With a temperature jump from 23 to 40 degrees C the film is switched from a swollen into a collapsed state. For the thin gold layer this switching is faster as compared to the thick gold layer. The switching is a two-step process of water release and a subsequent structural relaxation. fit swelling and deswelling cycles, aging of the films is probed. After five cycles, the film exhibits enhanced water storage capacity. Grazing-incidence small-angle X-ray scattering (GISAXS) shows that these gold coated nbc-PNIPAM films do not age with respect to the inner structure but slightly roughen at the gold surface. As revealed by atomic force microscopy, the morphology of the gold layer is changed by the water uptake and release.},
  language  = {en}
}