Pneumolysin/Plasma Protein Adsorption, Bacterial Adherence, and Cell Adhesion Characteristics of a Cell-Membrane-Mimicking Polymer System.

This study delivers the first report on a cell-membrane-mimicking polymer system, poly[oxy(4-(13-cholenoatenonyl)-1,2,3-triazoyl-1-methyl)ethylene--oxy(4-(13-phosphorylcholinenonyl)-1,2,3-triazoyl-1-methyl)ethylene] (PGA-CholPC) films in various compositions in terms of physicochemical properties, protein adsorptions, bacterial adherences, and human cell adhesions. Higher Chol-containing PGA-CholPC in a self-assembled multi-bilayer membrane structure is confirmed to show excellently high affinity to pneumolysin (a cytolysin) and its -terminal fragment (domain 4) but substantially suppressed affinity to the -terminal fragment (domains 1-3) and further to plasma proteins. Furthermore, the adherences of pathogenic bacteria are increased favorably; however, the adhesion and proliferation of a human HEp-2 cell line are hindered severely.

Newly Found Digital Memory Characteristics of Pyrrolidone- and Succinimide-Based Polymers.

This study reports for the first time the excellent nonvolatile and volatile digital memory characteristics of polymers bearing 2-pyrrolidone and succinimide moieties. A series of new polymers is synthesized from poly(ethylene-alt-maleic anhydride) and four alcohol derivatives with and without 2-pyrrolidone and succinimide moieties. All polymers, including polyvinylpyrrolidone, are found to be thermally stable up to 195 °C or higher, and characterized regarding their molecular orbital energy levels, bandgap, and resistive digital memory behaviors.

Seventeen-Armed Star Polystyrenes in Various Molecular Weights: Structural Details and Chain Characteristics.

Star-shaped polymers are very attractive because of their potential application ability in various technological areas due to their unique molecular topology. Thus, information on the molecular structure and chain characteristics of star polymers is essential for gaining insights into their properties and finding better applications. In this study, we report molecular structure details and chain characteristics of 17-armed polystyrenes in various molecular weights: 17-Arm(2k)-PS, 17-Arm(6k)-PS, 17-Arm(10k)-PS, and 17-Arm(20k)-PS.

Quantitative Structural Analysis of Polystyrene Nanoparticles Using Synchrotron X-Ray Scattering and Dynamic Light Scattering.

A series of polystyrene nanoparticles (PS-1, PS-2, PS-3, and PS-4) in aqueous solutions were investigated in terms of morphological structure, size, and size distribution. Synchrotron small-angle X-ray scattering analysis (SAXS) was carried out, providing morphology details, size and size distribution on the particles. PS-1, PS-2, and PS-3 were confirmed to behave two-phase (core and shell) spherical shapes, whereas PS-4 exhibited a single-phase spherical shape.

Phase Transition Behaviors and Nanoscale Film Morphologies of Poly(δ-valerolactone) Axles Bearing Movable and Fixed Rotaxane Wheels.

In this study, poly(δ-valerolactone) (PVL) axles bearing movable and fixed dibenzo-24-crown-8-ether wheels (rot-M and rot-F) are investigated for the first time in the terms of phase transition and nanoscale film morphology: PVL-rot-M and PVL-rot-F. Interestingly, the PVL axles reveal a strong tendency to form a horizontal lamellar structure with three different rotational crystal lattice domains in nanoscale films. The morphological structural parameters are discernibly varied by the movable and fixed rotaxane wheels.

Structural Characteristics of Pneumolysin and Its Domains in a Biomimetic Solution.

Pneumolysin (PLY) and its truncated fragments, domains 1-3 (D), and domain 4 (D), were purified as recombinant proteins after being cloned and over-expressed in . The three-dimensional structures of these proteins were quantitatively investigated in a biomimetic condition, phosphate buffered saline (PBS) by synchrotron X-ray scattering. X-ray scattering analysis revealed important structural features including structural parameters.

Digital Memory Characteristics of Aromatic Polyimides Based on Pyridine and Its Derivatives.

Soluble aromatic polyimides and polyvinyls were prepared by incorporating pyridine moiety and its derivatives in the backbone and the side groups, respectively: 6F-Py- polymers based on the polyimide backbone (6F-Py-1 to 6F-Py-7) and PVPy- polymers based on the polyvinyl backbone (PVPy-1 to PVPy-4). All polymers were found to be amorphous. The 6F-Py- polymers were thermally stable up to 511-545 °C; the PVPy- polymers were stable up to 362-376 °C.

Precise Synthesis, Properties, and Structures of Cyclic Poly(ε-caprolactone)s.

Cyclic PCL (-PCL) has drawn great attention from academia and industry because of its unique, unusual structure and property characteristics due to the absence of end groups in addition to the biocompatibility and biodegradability of its linear analogue. As a result of much research effort, several synthetic methods have been developed to produce -PCLs so far. Their chain, morphology and property characteristics were investigated even though carried out on a very limited basis.

A Comparative Study of Dynamic Light and X-ray Scatterings on Micelles of Topological Polymer Amphiphiles.

Micelles were prepared in organic solvents by using three topological polymer amphiphiles: (i) poly(-decyl glycidyl ether--2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether) (-PDGE--PTEGGE) and (ii) its analogue (-PDGE--PTEGGE); (iii) poly(6-phosphorylcholinehexylthiopropyl glycidyl ether---dodecanoyl glycidyl ether) (-PPCGE--PDDGE). For the individual micelle solutions, the size and distribution were determined by dynamic light scattering (DLS) and synchrotron X-ray scattering analyses. The synchrotron X-ray scattering analysis further found that -PDGE--PTEGGE forms oblate ellipsoidal micelle in an ethanol/water mixture, -PDGE--PTEGGE makes prolate ellipsoidal micelle in an ethanol/water mixture, and -PPCGE--PDDGE forms cylindrical micelle in chloroform.

Nanoscale Film Morphology and n-Type Digital Memory Characteristics of π-Conjugated Donor-Acceptor Alternating Copolymer Based on Thiophene and Thiadiazole Units.

Various molecular weight π-conjugated donor-acceptor polymers based on thiadiazole and thiophene units are investigated with respect to nanoscale film morphology and digital memory performance. Interestingly, all polymers reveal excellent n-type digital permanent memory characteristics, which are governed by the combination of Ohmic and trap-limited space charge limited conductions via a hopping process using thiadiazole and thiophene units as charge traps and stepping stones. The digital memory performance is significantly influenced by the film morphology details that vary with the polymer molecular weight as well as the film thickness.

Bacillus licheniformis α-amylase: Structural feature in a biomimetic solution and structural changes in extrinsic conditions.

Bacillus licheniformis α-amylase (BLA) in a biomimetic buffer and extrinsic solutions (various pH values, temperatures, and metal ions) has been investigated for the first time in the view of three-dimensional (3D) structure by synchrotron X-ray and dynamic light scattering analyses. BLA in buffer is determined to have a structure resembling its crystallographic structure; but the 3D structure is slightly larger than the crystal structure. Such a structure is maintained with little variations in extrinsic solutions of pH 4.

Pronounced Side Chain Effects in Triple Bond-Conjugated Polymers Containing Naphthalene Diimides for n-Channel Organic Field-Effect Transistors.

Three triple bond-conjugated naphthalene diimide (NDI) copolymers, poly{[ N, N'-bis(2-R)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-[(2,5-bis(2-R)-1,4-phenylene)bis(ethyn-2,1-diyl)]} (PNDIR-R), were synthesized via Sonogashira coupling polymerization with varying alkyl side chains at the nitrogen atoms of the imide ring and 2,5-positions of the 1,4-diethynylbenzene moiety. Considering their identical polymer backbone structures, the side chains were found to have a strong influence on the surface morphology/nanostructure, thus playing a critical role in charge-transporting properties of the three NDI-based copolymers. Among the polymers, the one with an octyldodecyl (OD) chain at the nitrogen atoms of imide ring and a hexadecyloxy (HO) chain at the 2,5-positions of 1,4-diethynylbenzene, P(NDIOD-HO), exhibited the highest electron mobility of 0.

Self-Assembling Brush Polymers Bearing Multisaccharides.

Three different series of brush polymers bearing glucosyl, maltosyl, or maltotriosyl moiety at the bristle end are successfully prepared by using cationic ring-opening polymerization and two sequential postmodification reactions. All brush polymers, except for the polymer containing 100 mol% maltotriosyl moiety, demonstrate the formation of multibilayer structure in films, always providing saccharide-enriched surface. These self-assembling features are remarkable, regarding the bulkiness of saccharide moieties and the kink in the bristle due to the triazole linker.

Self-Assembly-Assisted Biomolecule-Enriched Surface and High Selectivity Performance of Simple Solution-Coatable Biomimicking Brush Copolymers.

Poly(oxy(11-(biotinyl)undecylthiomethyl)ethylene-co-oxy(11-phosphoryl-cholineundecylthiomethyl)ethylene)s (PECH-BTmPCn: m = 0-100 mol % biotin (BT)-containing bristle; n = 100-0 mol % phosphorylcholine (PC)-containing bristle) were newly synthesized. All polymers exhibited excellent solution processability. They favorably self-assembled horizontal multibilayer structures in thin films with BT- and PC-enriched surfaces, which were driven by the lateral ordering of the fully extended upright bristles and the partial interdigitation between the BT and PC end groups of the bristles.

Well-defined hollow nanochanneled-silica nanospheres prepared with the aid of sacrificial copolymer nanospheres and surfactant nanocylinders.

A new approach for synthesizing well-defined hollow nanochanneled-silica nanosphere particles is demonstrated, and the structural details of these particles are described for the first time. Positively charged styrene copolymer nanospheres with a clean, smooth surface and a very narrow size distribution are synthesized by surfactant-free emulsion copolymerization and used as a thermal sacrificial core template for the production of core-shell nanoparticles. A surfactant/silica composite shell with a uniform thickness is successfully produced and deposited onto the polymeric core template by charge density matching between the polymer nanosphere template surface and the negatively charged silica precursors and then followed by selective thermal decomposition of the polymeric core and the surfactant cylinder domains in the shell, producing the hollow nanochanneled-silica nanospheres.

Clues to the electrical switching mechanism of carbazole-containing polyimide thin films.

The mechanism behind electrical memory behavior of carbazole-containing polyimides (PIs) in nanoscale thin films was investigated. For this investigation, a series of poly(3,3'-dihydroxy-4,4'-biphenylene-co-3,3'-bis(N-ethylenyloxycarbazole)-4,4'-biphenylene hexafluoro-isopropylidenedi-phthalimide)s (6F-HAB-HABCZn PIs) with various compositions was synthesized as a model carbazole-containing polymer system. The thermal properties, band gaps, and molecular orbital levels of the PIs were determined.

Self-assembly of novel lipid-mimicking brush polymers in nanoscale thin films.

A series of well-defined poly(oxy(11-phosphorylcholineundecylthiomethyl)ethylene-ran-oxy(n-dodecylthiomethyl)ethylene) (PECH-PCm: m = 0-100 mol% phosphorylcholine (PC)) polymers were used to prepare nanoscale thin films that were characterized by synchrotron X-ray reflectivity (XR) analysis. The quantitative XR analysis provided structural insights into the PECH-PCm thin films. The PECH-PC0 polymer film formed a well-ordered in-plane oriented molecular multibilayer structure, whose individual layers consisted of two sublayers.

Digital memory versatility of fully π-conjugated donor-acceptor hybrid polymers.

The fully π-conjugated donor-acceptor hybrid polymers Fl-TPA, Fl-TPA-TCNE, and Fl-TPA-TCNQ, which are composed of fluorene (Fl), triphenylamine (TPA), dimethylphenylamine, alkyne, alkyne-tetracyanoethylene (TCNE) adduct, and alkyne-7,7,8,8-tetracyanoquinodimethane (TCNQ) adduct, were synthesized. These polymers are completely amorphous in the solid film state and thermally stable up to 291-409 °C. Their molecular orbital levels and band gaps vary with their compositions.

Probing the self-assembled nanostructures of functional polymers with synchrotron grazing incidence X-ray scattering.

For advanced functional polymers such as biopolymers, biomimic polymers, brush polymers, star polymers, dendritic polymers, and block copolymers, information about their surface structures, morphologies, and atomic structures is essential for understanding their properties and investigating their potential applications. Grazing incidence X-ray scattering (GIXS) is established for the last 15 years as the most powerful, versatile, and nondestructive tool for determining these structural details when performed with the aid of an advanced third-generation synchrotron radiation source with high flux, high energy resolution, energy tunability, and small beam size. One particular merit of this technique is that GIXS data can be obtained facilely for material specimens of any size, type, or shape.

Structural Characteristics of Amphiphilic Cyclic and Linear Block Copolymer Micelles in Aqueous Solutions.

The structural characteristics of aqueous micelles composed of amphiphilic cyclic poly(-butyl acrylate--ethylene oxide) (cyclic PBA--PEO) or a linear analogue (i.e., linear poly(-butyl acrylate--ethylene oxide---butyl acrylate) (linear PBA--PEO--PBA)) were examined for the first time using synchrotron X-ray scattering techniques and quantitative data analysis.

Complex Self-Assembled Morphologies of Thin Films of an Asymmetric ABC Star Polymer.

An asymmetric nine-arm star polymer, (polystyrene)-(poly(4-methoxystyrene))-(polyisoprene) (PS-PMOS-PI) was synthesized, and the details of the structures of its thin films were successfully investigated for the first time by using in situ grazing incidence X-ray scattering (GIXS) with a synchrotron radiation source. Our quantitative GIXS analysis showed that thin films of the star polymer molecules have very complex but highly ordered and preferentially in-plane oriented hexagonal (HEX) structures consisting of truncated PS cylinders and PMOS triangular prisms in a PI matrix. This HEX structure undergoes a partial rotational transformation process at temperatures above 190 °C that produces a 30°-rotated HEX structure; this structural isomer forms with a volume fraction of 23% during heating up to 220 °C and persists during subsequent cooling.

Tunable Film Morphologies of Brush-Linear Diblock Copolymer Bearing Difluorene Moieties Yield a Variety of Digital Memory Properties.

An amphiphilic brush-linear diblock copolymer bearing a rigid difluorene moiety was synthesized, yielding a copolymer with a high thermal stability and excellent processability. The immiscibility of the blocks induced the formation of a variety of nanostructures, depending on the fabrication conditions, which differed significantly from the nanostructures observed among common diblock copolymers in similar composition. Interestingly, the orientations of the nanostructures could be controlled.

Morphology-driven high-performance polymeric photodetector.

The influence of polymer/fullerene morphology on photodetector performance is reported. Various morphologies of spin-coated films are generated by different blending ratio. Morphological study combined with measurement of charge carrier mobility reveals that blend films with an excess content of crystalline fullerene have a phase-separated morphology, resulting in enhanced charge carrier mobility.

Programmable bipolar and unipolar nonvolatile memory devices based on poly(2-(N-carbazolyl)ethyl methacrylate) end-capped with fullerene.

A novel polymer, poly(2-(N -carbazolyl)ethyl methacrylate) end-capped with fullerene (PCzMA-C(60) ), has been synthesized via living anionic polymerization. Electrically programmable flash memory devices were easily fabricated with this polymer by using solution coating and metal deposition. This polymer was found in these devices to exhibit bipolar and unipolar switching behaviors with a high ON/OFF current ratio, a long retention time, high reliability, and low power consumption.

Effects of side-chain interdigitation on stability: an environmentally, electrically, and thermally stable semiconducting polymer.

A polymeric semiconductor, poly(3,6-dihexyl-[2,2']bi[thieno[3,2-b]thiophene]) (PDHTT), was synthesized and tested as an active layer in organic thin film transistors (OTFTs). This semiconductor showed considerable potential for use in commercial electronic devices because of its superior characteristics, particularly its good stability. PDHTT-based OTFTs exhibited high stability in air, retaining their initial performance after exposure to 70% relative humidity for 50 days; they were also stable under repeated electrical stress and even after exposure to temperatures as high as 250 °C.