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In this study, the molecular arrangement and surface morphology of organized molecular films of cyclic moiety-containing polyguanamine derivatives with a flexible linker moiety were investigated. The cyclic moiety-containing polyguanamine derivatives with bulky aromatic ring linkers were amorphous in the bulk state, but a crystalline packing was achieved in two-dimensional molecular films. In contrast, the cyclic moiety-containing polyguanamine derivatives with flexible linker moieties were amorphous in the bulk state and in the two-dimensional molecular film. In addition, although the multiple hydrogen bonds responsible for the intermolecular interactions were enhanced during the formation of the two-dimensional film of the derivatives with aromatic ring linker moieties, these interactions were more pronounced in the bulk state of the derivatives with flexible linker moieties. Furthermore, the two-dimensional films of the derivatives containing flexible linker moieties exhibited an extremely uniform and smooth surface morphology; however, the derivatives containing aromatic ring linker moieties had several defects and exhibited an inhomogeneous surface morphology. Moreover, although the polyguanamine derivatives with flexible linker moieties were amorphous even in the two-dimensional molecular film state, they maintained the metal-scavenging ability of the cyclic moiety. The derivatives that scavenged the metal cation tended to transit to a more sophisticated layered regularity. [ABSTRACT FROM AUTHOR]

"Metal collection" by a monolayer of polyguanamine derivatives with a cyclic component and a flexible linker moiety can be realized at an air/water interface. Distinct differences between the properties of the two derivatives were confirmed for the desorption behavior of Pd2+ ions. The cyclic moiety that resulted from the formation of the organized films of the polyguanamine derivatives exhibited a cup-shaped conformation rather than a planar conformation. Since Cd2+ ions have the same valence as Pd, there was no significant difference between the interfacial monolayer of these derivatives in the collection behavior from the subphase. The origin of the observed difference is likely the tilt angle of the cyclic site due to the substitution of a linker unit. The combination of the distortion angle of the cyclic component and the ionic radius may produce a structure for which desorption of the collected metal cations is difficult. [Display omitted] • Metal collection by polyguanamine derivatives with flexible linker was realized. • The cyclic part of polyguanamine derivatives exhibited cup-shaped conformation. • Substitution of the linker moiety affected the metal uptake/desorption ability. • Substitution of the linker moiety consequently affected the distortion angle of the cyclic part. • Depending on distortion angle of cup-conformation, it difficult for collected metal to desorb. [ABSTRACT FROM AUTHOR]

Highlights: [•] DNA adsorbs to diamino-s-triazine ring in comb polymer monolayer by hydrogen bonding. [•] Newly binary comb copolymers containing s-triazine behaves as an adsorption template. [•] Adsorbed DNA forms circular domains have 50–60nm diameters. [•] Aggregated π-conjugated system of DNA in film emits fluorescence with sharper band. [Copyright &y& Elsevier]

Abstract: Interlayer energy transfer from perylene diimide (PDI12) layers to phthalocyanine layers was studied using steady-state absorption, fluorescence, and time-resolved fluorescence and microscopy methods. The layers were prepared by Langmuir–Schäfer method, spaced by a few layers of octadecylamine deposited by Langmuir–Blodgett method, when required. The fluorescence lifetime microscopy method allowed to exclude defects from the energy transfer analysis and calculate the fluorescence lifetimes of PDI12 for the defect free areas. The estimated distance dependence of the interlayer energy transfer follows roughly second order dependences on the distance with the critical distance of 6.9nm. [Copyright &y& Elsevier]

With comb polymers with different kinds of fluorocarbon side-chains, significant effects of spreading solvents on the monolayers at the air/water interface and the molecular arrangement in the deposited films could be found by the use of trifluoroacetic acid and its mixed solvents with n-hexane, depending on the atoms, fluorine or hydrogen, substituted at the end of the fluorocarbon side-chains. These facts are probably due to intralayer hydrogen bonding cooperating with the carbonyl groups of the long-chain esters. The deposited films of solid substrates were characterized by polarized near-edge X-ray absorption fine structure (NEXAFS) spectroscopy as well as in-plane X-ray diffraction and scanning electron and atomic force microscopy. [Copyright &y& Elsevier]

Azobenzene (Az)-containing polymers provide fascinating photoresponsive actuation systems. When they are organized at interfaces, the motion of Az unit occurring at a molecular (sub-nano) scale can be transferred and amplified to larger scales of materials. This review article focuses to selected research topics on organized layer systems of Az-containing polymers proceeding in our laboratory. They involve i) photomechanical response of monolayers at nanometer levels in thickness and centimeters in area, ii) monolayer-mediated photoorientation of polymer (polysilane) and mesoporous silica at nano- to sub-micrometer levels in thickness, and iii)instant mass migration triggered by patterned photoirradiation occurring at distances over micrometer levels. In every system, strong cooperative interplays between the Az unit and organized molecular or macromolecular assemblies play the essential roles. Promotions of these research areas are anticipated to provide wide and new opportunities for material processing and creation of new classes of photofuncitional soft materials. [ABSTRACT FROM AUTHOR]

The morphologies of monolayers containing Eu(TTA)3Phen (TTA = thenoyltrifluoroacetone, Phen = 1, 10-phenanthroline) were studied at the air/liquid interface on different subphases by fluorescence microscopy (FM). The composite subphase was the basic premise for the stable existence of the rare earth compound at air/liquid interface. The process that rare earth compound phase changes from liquid expanded state to liquid condensed state corresponded to a plateau in the π-A isotherm. In the pure Eu(TTA)3Phen monolayer, rod domains of Eu(TTA)3Phen formed and packed with no order. In the mixed monolayers with stearic acid (SA), phase transition of SA occurred first and formed domains with an electric gradient field, which induced the rare earth compound to form luminescent ring domains. Influence of intermolecular interaction on the self-organized microstructure was revealed. [ABSTRACT FROM AUTHOR]