TY  - JOUR
A1  - Anton, Arthur Markus
A1  - Steyrleuthner, Robert
A1  - Kossack, Wilhelm
A1  - Neher, Dieter
A1  - Kremer, Friedrich
T1  - Infrared Transition Moment Orientational Analysis on the Structural Organization of the Distinct Molecular Subunits in Thin Layers of a High Mobility n-Type Copolymer
JF  - Journal of the American Chemical Society
N2  - The IR-based method of infrared transition moment orientational analysis (IR-TMOA) is employed to unravel molecular order in thin layers of the semiconducting polymer poly[N,N'-bis(2-octyldodecyl),-1,4,5,8-naphthalene-diimide-2,6-diyl]-alt-5-5'-(2,2'-bithiophene) (P(NDI2OD-T2)). Structure-specific vibrational bands are analyzed in dependence On polarization and inclination of the sample-With respect to the optical axis. By that the molecular Order parameter tensor for the respective molecular moieties with regard to the sample: coordinate system is deduced. Making use of the specificity of the IR spectral range, we are able to determine separately the orientation of atomistic planes defined through the naphthalenediimide (NDI) and bithiophene (T2) units relative to the substrate, and hence, relative to each other. A pronounced solvent effect is observed While chlorobenzene causes the T2 planes to align preferentially parallel to the substrate at an angle of 29 degrees, using a 1:1 chloronaphthalene:xylene mixture results in a reorientation of the T2 units from a face on into an edge on arrangement. In contrast the NDI unit remains unaffected. Additionally, for both solvents evidence is observed for the aggregation of chains in accord With recently published results obtained by UV-vis absorption spectroscopy.
Y1  - 2015
U6  - https://doi.org/10.1021/jacs.5b01755
SN  - 0002-7863
VL  - 137
IS  - 18
SP  - 6034
EP  - 6043
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kathrein, Christine C.
A1  - Kipnusu, Wycliffe K.
A1  - Kremer, Friedrich
A1  - Böker, Alexander
T1  - Birefringence Analysis of the Effect of Electric Fields on the Order-Disorder Transition Temperature of Lamellae Forming Block Copolymers
JF  - Macromolecules : a publication of the American Chemical Society
N2  - A detailed birefringence analysis of the effect of strong dc electric fields on the order-disorder transition temperature (T-ODT) of lamella forming block copolymers is reported. The setup presented here enabled the measurement of the T-ODT with high temperature resolution while the birefringence measurements were nondestructive and straightforward compared to alternative methods. A downward shift in the transition temperature was found for all samples upon application of the electric field. The data indicate that the dominating parameter that evokes the mixing of block copolymers when exposed to electric fields is the difference in dielectric permittivity Delta epsilon between the block copolymer constituents. The extent to which the T-ODT is shifted is furthermore influenced by the degree of polymerization N. Shifts in the transition temperature of up to 7 degrees C were found upon application of an electric field of 5 kV/mm.
Y1  - 2015
U6  - https://doi.org/10.1021/acs.macromol.5b00512
SN  - 0024-9297
SN  - 1520-5835
VL  - 48
IS  - 10
SP  - 3354
EP  - 3359
PB  - American Chemical Society
CY  - Washington
ER  -