In this study, poly(N-alkyl acrylamides) [(pAlkylAms)], which contain alkyl side chains that differ with respect to the chain length (n; n = 4− 18), were synthesized and the formation of lamellar structures via nanophase separation was examined. Differential scanning calorimetry (DSC) measurements indicated that p(AlkylAms) (n = 4−15) powders are amorphous at 20 °C, whereas p(AlkylAms) (n ≥ 16) contain partially crystalized side chains. The Xray diffraction (XRD) patterns of the spin-coated films of p(AlkylAms) (n = 4− 15) exhibited broad diffraction peaks that correspond to the nanosegregated alkyl side chain domains (q nd ), while the spectra of the polymer films of p(AlkylAms) (n ≥ 16) exhibited both q nd and diffraction corresponding to crystalized side chains (q ca ). The spin-coated films were annealed in water (water annealing) for 12 h to induce nanophase separation and then characterized using XRD. The XRD results for the water-annealed films were categorized into three groups. The first group comprised of p(AlkylAms) (n = 4−7), which showed XRD patterns similar to those of the pristine films. The second group contained p(AlkylAms) (n = 8−14), which exhibited strong Bragg diffraction peaks that correspond to lamellar structures (q lm ). The last group was composed of p(AlkylAms) (n ≥ 15), which exhibited not only q lm but also q ca . The results indicate that in p(AlkylAms) (n ≥ 8), the nanosegregation force between the hydrophilic main chain and the hydrophobic side chains is sufficient to produce an amorphous film with a lamellar structure. Furthermore, based on a comparison of the lamellar structure of p(AlkylAms) (n = 18) prepared by conventional thermal annealing with the structure obtained using water annealing, we concluded that nanosegregation competes with side-chain crystallization.

Highly oriented lamellar films of poly(N-dodecylacrylamide) with high molecular weights were formed by nanosegregation between alkyl side chains and a water-adsorbed main chain.

An anisotropic proton conductive polymer film was prepared from poly(decylacrylamide-co-12-acrylamidododecanoic acid). The polymer film was prepared on a solid substrate by spin coating and the structure was analyzed by X-ray diffraction measurement. The initial polymer film exhibited featureless diffraction, which indicates that the film was amorphous. On the other hand, when the film was annealed at 60°C under 98% RH, the film structure was converted from amorphous to highly oriented lamellar structure. The proton conductivities of the film parallel and perpendicular to the substrate surface were studied by impedance measurement. The conductivity at the parallel direction increase whereas that at the perpendicular direction decrease with measurement time. This is because the film formed a lamellar structure in-situ during the proton conductivity measurement. In other words, the anisotropic conduction state can be reached as long as the proton conductivity measurements were carried out.

We report a biomimetic polyelectrolyte based on amphiphilic polymer nanosheet multilayer films. Copolymers of poly(N-dodecylacrylamide-co-vinylphosphonic acid) [p(DDA/VPA)] form a uniform monolayer at the air−water interface. By depositing such monolayers onto solid substrates using the Langmuir−Blodgett (LB) method, multilayer lamellae films with a structure similar to a bilayer membrane were fabricated. The proton conductivity at the hydrophilic interlayer of the lamellar multilayer films was studied by impedance spectroscopy under temperature-and humiditycontrolled conditions. At 60 °C and 98% relative humidity (RH), the conductivity increased with increasing mole fraction of VPA (n) up to 3.2 × 10 −2 S cm −1 for n = 0.41. For a film with n = 0.45, the conductivity decreased to 2.2 × 10 −2 S cm −1 despite the increase of proton sources. The reason for this decrease was evaluated by studying the effect of the distance between the VPAs (l VPA ) on the proton conductivity as well as their activation energy. We propose that for n = 0.41, l VPA is the optimal distance not only to form an efficient two-dimensional (2D) hydrogen bonding network but also to reorient water and VPA. For n = 0.45, on the other hand, the l VPA was too close for a reorientation. Therefore, we concluded that there should be an optimal distance to obtain high proton conductivity at the hydrophilic interlayer of such multilayer films.