% 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”. @ARTICLE{Goracci:827713, author = {Goracci, G. and Arbe, A. and Alegría, A. and Su, Y. and Gasser, U. and Colmenero, J.}, title = {{S}tructure and component dynamics in binary mixtures of poly(2-(dimethylamino)ethyl methacrylate) with water and tetrahydrofuran: {A} diffraction, calorimetric, and dielectric spectroscopy study}, journal = {The journal of chemical physics}, volume = {144}, number = {15}, issn = {1089-7690}, address = {Melville, NY}, publisher = {American Institute of Physics}, reportid = {FZJ-2017-01821}, pages = {154903 -}, year = {2016}, abstract = {We have combined X-ray diffraction, neutron diffraction with polarization analysis, small angle neutron scattering, differential scanning calorimetry, and broad band dielectric spectroscopy to investigate the structure and dynamics of binary mixtures of poly(2-(dimethylamino)ethyl methacrylate) with either water or tetrahydrofuran (THF) at different concentrations. Aqueous mixtures are characterized by a highly heterogeneous structure where water clusters coexist with an underlying nano-segregation of main chains and side groups of the polymeric matrix. THF molecules are homogeneously distributed among the polymeric nano-domains for concentrations of one THF molecule/monomer or lower. A more heterogeneous situation is found for higher THF amounts, but without evidences for solvent clusters. In THF-mixtures, we observe a remarkable reduction of the glass-transition temperature which is enhanced with increasing amount of solvent but seems to reach saturation at high THF concentrations. Adding THF markedly reduces the activation energy of the polymer β-relaxation. The presence of THF molecules seemingly hinders a slow component of this process which is active in the dry state. The aqueous mixtures present a strikingly broad glass-transition feature, revealing a highly heterogeneous behavior in agreement with the structural study. Regarding the solvent dynamics, deep in the glassy state all data can be described by an Arrhenius temperature dependence with a rather similar activation energy. However, the values of the characteristic times are about three orders of magnitude smaller for THF than for water. Water dynamics display a crossover toward increasingly higher apparent activation energies in the region of the onset of the glass transition, supporting its interpretation as a consequence of the freezing of the structural relaxation of the surrounding matrix. The absence of such a crossover (at least in the wide dynamic window here accessed) in THF is attributed to the lack of cooperativity effects in the relaxation of these molecules within the polymeric matrix.}, cin = {JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II / JCNS-2}, ddc = {540}, cid = {I:(DE-Juel1)JCNS-FRM-II-20110218 / I:(DE-Juel1)JCNS-2-20110106}, pnm = {6G15 - FRM II / MLZ (POF3-6G15) / 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623)}, pid = {G:(DE-HGF)POF3-6G15 / G:(DE-HGF)POF3-6G4}, experiment = {EXP:(DE-MLZ)DNS-20140101}, typ = {PUB:(DE-HGF)16}, UT = {WOS:000375786000040}, doi = {10.1063/1.4946004}, url = {https://juser.fz-juelich.de/record/827713}, }