Solid-State NMR Investigation of Morphology in Poly(N-vinylcarbazole) Complexes with Poly(ethylene glycol) Monomethyl Ether 3,5-Dinitrobenzoate

Interactions and morphology were investigated by solid-state NMR in macromolecular charge transfer (CT) complexes formed between poly( N -vinylcarbazole) (PVK) and a surfactant consisting of a monomethyl ether poly(ethylene glycol) (PEG) oligomer functionalized at one end with a 3,5-dinitrobenzoyl (DNB) group. 13 C CP MAS NMR spectra indicated that in the PVK/PEG−DNB complexes containing 33.1 and 50.0 mol % PEG−DNB, the PEG chains undergo microphase separation. The balance between the PVK/DNB CT interactions and the repulsion between the PVK backbone and the PEG side chains produces comblike structures similar to those observed in polyelectrolyte/surfactant complexes. The size of the domains in these microphase-separated comblike CT complexes was evaluated on the basis of proton spin−lattice relaxation time in the rotating frame [ T 1 ρ (H)] and spin diffusion data. Assuming a lamellar morphology, the PEG microdomain is about 3 nm thick. The size of the PVK/DNB microdomains was estimated at about 5 nm, suggesting that the PVK chains must be oriented perpendicular to the direction of the domain thickness, in the layer plane, the layer thickness being given by about two to three PVK chains.