Supramolecular Assembly of Gold Nanoparticles Mediated by Polypseudorotaxane with Thiolated β‐Cyclodextrin

Summary: A water‐soluble gold nanoparticle aggregate 2 was prepared by chloroauric acid and a polypseudorotaxane 1 of mono‐6‐thio‐β‐cyclodextrin with poly(propylene glycol) bis(2‐aminopropyl ether) ( ≈ 2 000) in the presence of sodium borohydride in N,N‐dimethylformamide (DMF) solution. The investigative results indicated that the gold nanoparticle aggregate 2 might act as an efficient DNA‐cleavage reagent.

A typical TEM image of gold nanoparticle aggregate 2 .     

Chemical Modification of Chitosan, 17

The Michael reaction of chitosan with acrylic acid was carried out successfully, even in water alone as the reaction medium. As a consequence of its good solubility in water, the reaction product, N‐carboxyethylchitosan, showed excellent biodegradable properties with standard activated sludge.

     

Hydrodynamic Effect on Secondary Phase Separation in an Epoxy Resin Modified with Polyethersulfone

Summary: The evolution of the morphologies in blends of epoxy/4,4′‐methylenebis(2,6‐dimethylaniline)/polyethersulfone was followed by time‐resolved light scattering, optical microscopy and scanning electron microscopy. The results suggest that, once the diffusion of epoxy molecules cannot follow the geometrical growth, a secondary phase separation occurs, even in the droplet morphology, in which the size of the epoxy‐rich domain grows as usual. The viscoelastic effect of polyethersulfone is also discussed.

Development of morphologies followed by OM: bicontinuous phase separation in the PES‐15.9 blend cured at 140 °C after 80 s.     

Polyurethanes Containing Indole‐Based Non‐Linear Optical Chromophores: from Linear Chromophore to H‐Type

Two new “H” type of indole‐based chromophores were designed and successfully introduced to the polymeric system, the resultant polymers demonstrated enhanced NLO effects, good processability, thermal stability and nearly excellent transparency, indicating the advantages of “H” type chromophore moieties. And they could be promising candidates for the practical applications as new photonic materials.

     

Dual Self‐Assembling Polycondensation of p‐Acetoxybenzoic Acid and p‐Acetamidobenzoic Acid

The dual self‐assembling polycondensation of p‐acetoxybenzoic acid (ABA) and p‐acetamidobenzoic acid in Therm S 800 was examined at 300 °C. Needle‐like crystals and lath‐like crystals were formed simultaneously through reaction‐induced crystallization of oligomers at a molar ratio of 30–50 mol‐% ABA in the feed. The needle‐like crystals comprised more p‐oxybenzoyl units, whereas the lath‐like ones contained higher amounts of p‐benzamide moieties.

     

Synthesis of Aromatic Macrocyclic Amphiphiles and their Self‐Assembling Behavior in Aqueous Solution

A triblock amphiphilic macrocycle consisting of a macrocyclic aromatic segment, a hydrophilic oligo(ethylene oxide) branch, and a hydrophobic alkyl dendron is successfully synthesized and characterized. The resulting cyclic amphiphile is observed to self‐assemble into hollow double‐layered capsules in aqueous solution, as confirmed by dynamic light scattering and cryogenic transmission electron microscopy investigations. The capsules are able to encapsulate hydrophobic guest molecules through aromatic interactions with high stability.

     

All‐Conjugated,Rod‐Rod Block Copolymers‐Generation and Self‐Assembly Properties

Based on their rigid‐rod structure all‐conjugated, rod‐rod block copolymers show a preferred tendency to self‐assemble into low‐curvature vesicular or lamellar nanostructures independent from their specific chemical structure and composition. This unique and attractive behaviour is clearly illustrated in a few examples of such all‐conjugated block copolymers. The resulting nanostructured heteromaterials may find applications in electronic devices or artificial membranes.

     

Enhancement of Photostability in Blue‐Light‐Emitting Polymers Doped with Gold Nanoparticles

A dramatic increase in the photostability of a blue‐light‐emitting polymer, poly(9,9‐dioctylfluorene), was achieved by the addition of 5–10 nm gold nanoparticles. The optical absorption band of the gold nanoparticles was tuned to resonate the triplet exciton ground state bandgap energy of the polymer. Photo‐oxidation rate of poly(9,9‐dioctylfluorene) was effectively reduced by doping the polymer with very small amounts (≈10⁻⁶–10⁻⁵ volume fraction) of the gold nanoparticles.

Retarded photo‐oxidation in PDOF nanocomposite films with various doped gold nanoparticles.     

An Efficient and Environmentally Friendly Method for the Synthesis of Cellulose Carbamate by Microwave Heating

An efficient, solvent‐free, and catalyst‐free microwave synthesis of cellulose carbamate from a mixture of native cellulose and urea is reported. The structure of the samples are characterized by elemental analysis, FT‐IR spectroscopy, X‐ray diffraction, and NMR spectrometry. Cellulose carbamates with a nitrogen content of 0.651–2.427% are obtained by microwave heating at 255 W for 2–5 min. With the introduction of carbamate groups, the hydrogen bonding and crystalline structure of the native cellulose are partially destroyed. The products retain the cellulose I crystalline form of the native cellulose, and display good solubility in NaOH solutions.

     

Sorption of Hydrophobic Organic Compounds by Aqueous Latexes

Summary: Optical absorption measurements are used for the first time to investigate the uptake of pure organic solvents or solutions by latex particles. Sorption into glassy polymer particles is a two‐stage process with distinctly different characteristic times, which reflects that an initial softening of the outer particle layer facilitates further uptake. The sorption of solutions containing highly water‐insoluble compounds allows the preparation of composite nanoparticles, which are hardly accessible by other routes.

Photograph of the neat 100 nm latex (right) particles and the particles after dying by sorption with the hydrophobic pigment Sudan IV (left).     

Multi‐Morphological Complex Aggregates Formed from Amphiphilic Poly(ethylene oxide)‐block‐Polydimethylsiloxane‐block‐Poly(ethylene oxide) Triblock Copolymers

Summary: Amphiphilic triblock copolymers (PEO_x‐b‐PDMS_y‐b‐PEO_x) with different block lengths were synthesized and multi‐morphological complex crew‐cut, star‐like, and short‐chain aggregates were prepared by self‐assembly of the given copolymers. The morphologies and dimensions of the aggregates can be well controlled by variation of the preparation conditions. TEM, SEM, FFR‐TEM, and LLS studies show the resulting morphologies range from LCMs, unilamellar or multilayer vesicles, LCVs, porous spheres to nanorods.

TEM images of the vesicles formed from PEO‐b‐PDMS‐b‐PEO.     

Surface‐Imprinted,Thermosensitive, Core‐Shell Nanosphere for Molecular Recognition

Summary: The D ‐glucose imprinted core‐shell nanosphere with an average size of ≈60 to 80 nm showed a significant preference for the binding of D ‐glucose than the non‐imprinted core‐shell nanosphere. Depending on temperature, the binding site in the shell with N‐isopropylacrylamide oligomer underwent a significant change in binding affinity. In addition, the D ‐glucose imprinted core‐shell nanosphere showed a two times higher affinity for D ‐glucose than L ‐glucose, suggesting chiral recognition of the binding site. The core‐shell nanosphere reported here is a good biomimetic model system with a well‐defined morphology, high surface area, and variable binding affinity through a change in temperature.

D ‐glucose imprinted core‐shell nanospheres showed excellent binding over the non‐imprinted core‐shell nanosphere.     

Construction of a Hexameric Zn(II)‐metallomacrocycle and its Photo‐ and Electroluminescence Properties: [Zn6(O‐hexyl‐3,5‐bis(2,2′:6′,2″‐terpyridine)phenol)6(BF4)12]

Summary: An O‐hexyl‐3,5‐bis(terpyridine)phenol ligand has been synthesized and transformed into a hexagonal Zn(II)‐metallomacrocycle by a facile self‐assembly procedure capitalizing on terpyridine‐Zn(II)‐terpyridine connectivity. The structural composition was confirmed by NMR and mass spectral techniques; photo‐ and electroluminescence properties were also investigated. The OLED device shows green electroluminescent emission at 515 nm with a maximum luminance of 39 cd · m⁻² and maximum efficiency of 0.16 cd · A⁻¹.

Structure and electroluminescent properties of the metallomacrocycle investigated.     

Fabrication of Mussel‐Inspired Highly Adhesive Honeycomb Films Containing Catechol Groups and Their Applications for Substrate‐Independent Porous Templates

Porous surface patterns are used in a wide variety of practical applications. Honeycomb‐patterned porous polymer films are good templates for preparing porous surfaces due to their simple fabrication and the arrangement of pores on the surface. Catechol groups include in adhesive protein of mussels have attracted much attention due to their highly and substrate‐independent adhesive properties. In this paper, highly and substrate‐independent adhesive honeycomb‐patterned porous polymer films are prepared by using amphiphilic copolymer having catechol moieties. Furthermore, porous surface patterns are transferred on various organic or inorganic substrates by wet etching with using adhesive honeycomb films as templates.

     

Synthesis with Single Macromolecules: Covalent Connection between a Neutral Dendronized Polymer and Polyelectrolyte Chains as well as Graphene Edges

Single chains of a neutral, dendronized polymer with peripheral azide groups ( PG3A ) are co‐deposited onto molecularly modified graphite substrates with a positively charged dendronized polymer ( PG2 ) as well as with negatively charged plasmid dsDNA. PG3A is also prepared near graphite step‐edges. Single PG3A chains are moved with a scanning force microscope tip, into close contact with either of the two polyelectrolytes, as well as the step‐edge at predetermined positions. Treating these structures in situ with UV light leads to photochemically induced cross‐linking between the PG3A chains carrying azide groups and PG2 , dsDNA, and graphite step‐edges, respectively, which is proven by mechanically challenging the “welding” points by pulling on the molecules with the SFM‐tip.

     

Temperature‐Sensitive Poly(N‐isopropylacrylamide) Hydrogels with Macroporous Structure and Fast Response Rate

Macroporous temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPA) hydrogels were prepared by a novel phase‐separation technique to improve the response properties. In comparison with a conventional PNIPA hydrogel prepared in water, these macroporous hydrogels, prepared by polymerization in aqueous sucrose solutions, have higher swelling ratios at temperatures below the lower critical solution temperature and exhibit much faster response rates to temperature changes.

Scanning electron microscopy image of the surface of a PNIPA hydrogel, prepared in 1.50 M aqueous sucrose solution.     

Effect of the Molecular Weights of Poly‐L‐Arginine on Membrane Strength and Permeability of Poly‐L‐Arginine Group Microcapsules

A novel poly‐L ‐arginine group microcapsule was produced to investigate its nutritional function and pharmacological efficacy. The molecular weight of poly‐L ‐arginine is an important parameter for its membrane strength, but does not obviously affect its release property. Thus, poly‐L ‐arginine can be used as a kind of new membrane material in microcapsules, and it is expected to be used as an therapeutic and biodegradable drug carrier.

Influence of the molecular weight of poly‐L ‐arginine on membrane thickness.     

Binary Reactive/Inert Non‐Fouling Polymeric Surfaces

Binary reactive/inert antifouling polymer brushes were grafted via a two step surface initiated polymerization from printed initiator monolayer and provided robust, effective polymeric surfaces for bioattachment with distinguishably reduced non‐specific adsorption. This synthetic strategy can be harnessed to build complex binary polymeric structures on substrate surfaces and the polymer brush surfaces reported in the present paper can be widely used for versatile biological study.

     

On‐Chip Alginate Microencapsulation of Functional Cells

We report the use of a PTFE‐based microfluidic device for the encapsulation of living, therapeutically‐active cells within monodisperse alginate microspheres. We present a novel microfluidic platform and a flexible experimental method for the production of alginate microspheres. Cell lines HEK293, U‐2 OS and PC12 were separately encapsulated using this method, with minimal loss of cell viability.