This paper is concerned with a novel layer-by-layer adsorption method for preparing multilayer assemblies of polymeric materials. We employed two kinds polymers, poly[2-(9-carbazolyl)ethyl methacrylate] and poly[2-[(3,5-dinitrobenzoyl)oxy]ethyl methacrylate], both bearing nonionic pendant groups in the side chains which have electron-donating character and electron-accepting character, respectively. These polymers were alternatively adsorbed onto the gold surface and the quartz substrates from the solutions in methylene chloride. The formation of this multilayer assembly is based on the charge-transfer (CT) interaction between these groups at the solid−liquid interface and the films obtained have periodic layers of CT complexes. The successive increase of the thickness could be easily monitored by surface plasmon measurements. The thickness increment increased with the increase in the number of layers, and the increment became constant around the 10th layer, indicating that the total thickness of the film increases linearly by the alternating adsorption of the counter polymer.

Organic materials with diverse molecular designs show multifunctional properties such as coupled ferroelectric, optical, ferromagnetic, and transport properties. We report the design of an alkylamide-substituted pyrene derivative displaying fluorescent ferroelectric properties coupled with electron transport properties. In solution phase, this compound displayed concentration-dependent fluorescence, whereas in xerogels, a fluorescent green organogel (>0.1 mM) and entangled nanofibers were observed. A discotic hexagonal columnar liquid crystalline phase was observed above 295 K due to intermolecular hydrogen bonding and π-stacking interactions. The direction of the hydrogen-bonded chains could be inverted by the application of an external electric field along the π-stacked column, resulting in ferroelectric polarization-electric field (P-E) hysteresis. The local electric field arising from the ferroelectric macrodipole moment arrangement along the π-stacking direction affected the electron transport properties on the π-stack of pyrenes, thus confirming the current-switching phenomena according to P-E hysteresis. We report that multifunctional properties such as ferroelectricity, fluorescence, and electron transport switching were successfully achieved in hydrogen-bonded dynamic π-molecular assemblies.

This paper describes the fabrication of hybrid nanoassemblies with polymer brushes and gold nanoparticles enabling detection of nanoscale optical changes based on localized surface plasmon resonance. The reversible and thermosensitive nanoscale actuation is achieved by combining stimuli-responsive polymer brushes and gold nanoparticles independently and selectively assembled on substrates. These hybrid nanoassemblies are assembled on numerous substrates and will be applicable for optoelectronics, nanoactuator, and nanosensor applications.

We describe here a polymer nanosheet assembly that serves as a molecular photoswitching and optical exclusive OR (EXOR) logic gate. Separate polymer nanosheets (monolayers) containing phenanthrene, anthracene, and dinitrobenzene chromophore were prepared by the Langmuir-Blodgett technique (LB films). A bilayer-couple, consisting of phenanthrene (sensitizer) monolayer and dinitrobenzene (acceptor) monolayer, and the other couple, of anthracene monolayer and dinitrobenzene monolayer, were confirmed to function as a photodiode showing current rectification on light irradiation. The two photodiodes are connected as each photocurrent direction becomes opposite. In the polymer photodiode array (LB films), anodic photocurrent was observed when the anthracene was selectively excited. On the other hand, cathodic photocurrent was observed by selective excitation of the phenanthrene. Moreover, the output photocurrent displayed a very small value when the phenanthrene and anthracene were excited simultaneously. The performance is discussed for this gate's application to an optical EXOR logic gate.

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 and ordered lamellar polymer film was prepared by simply annealing the poly(N-dodecylacrylamide) film under humid conditions.

A layer-by-layer film could be fabricated on a substrate by the consecutive adsorption method based on the charge-transfer (CT) interaction between electron-donating carbazolyl groups and electron-accepting 3,5-dinitrobenzoyl groups in the side chains of two kinds of methacrylate polymers, poly[2-(9-carbazolyl)ethyl methacrylate] (PCzEMA) and poly [2-[(3,5-dinitrobenzoyl)oxy]ethyl methacrylate] (PDNBMA), respectively. The film was characterized by surface plasmon (SP) and UV-vis absorption measurements. The thickness of each layer in the film could be determined by the SP measurements. In the UV-vis absorption measurements, the absorbance of the CT complex increased linearly with the increase in the number of adsorption cycles, indicating that the steady growth of the film took place by immersing the substrate alternatively in the 1,2-dichloroethane solutions of each polymer. Furthermore, the decrease in the absorbance of carbazolyl groups was observed on the immersion of the film with the PCzEMA surface in the solution of PDNBMA. This indicates the formation of the CT complex between adjacent polymer layers. The multilayered structure of the obtained film showed an excellent thermal stability up to 200 °C.

This Article describes a unique approach to building silsesquioxane nanoassemblies based on the Langmuir-Blodgett (LB) technique. Poly(N-dodecylacrylamide-co-3-methacryloxypropyl-T8-heptatrifluoropropyl (or heptaphenylpropyl) POSS)s (p(DDA/SQ)s) were synthesized through free radical copolymerization using propyl methacrylate-substituted polyhedral oligomeric silsesquioxane (POSS) monomers containing seven nonreactive trifluoropropyl or phenyl groups (R 7 (Si 8 O 12 )(CH 2 CH 2 CH 2 -OCOCH 3 CdCH 2 ) (where R is either trifluoropropyl (SQF) or phenyl (SQPh)) and amphiphilic copolymers. The p(DDA/SQ)s formed stable monolayers at the air/water interface. The monolayers were transferred onto solid substrates as Y-type LB films using a vertical dipping method. The polymer LB films had a well-defined layer structure and a surface flatness (rms values < 1 nm in 1 µm 2 ). The high heat-resistant properties of the p(DDA/SQ) LB films were demonstrated using UV-vis spectroscopic reflectometry and FT-IR. The refractive index and the thickness of the p(DDA/SQ) LB films were measured as functions of temperature. Upon heating, the refractive index of the p(DDA/SQPh) LB films increased from 1.43 (200 °C) to 1.49 (270 °C), whereas that of poly(N-dodecylacrylamide) (pDDA) decreased from 1.38 (200 °C) to 1.28 (220 °C), indicating a densely packed configuration of silsesquioxane units in thin films. A control experiment with pDDA LB films showed domain structures at temperatures greater than 200 °C, although the p(DDA/SQ) LB films remained uniform and smooth after heating to 320 °C. This bottom-up approach is promising for coating with organic and inorganic nanomaterials for optoelectric nanodevice applications.