A facile approach to prepare poly(3‐hexylthiophene) (P3HT)/cadmium selenide quantum dot (CdSe QD) hybrid coaxial nanowires by a stepwise self‐assembly process is reported. P3HT nanowires of ≈20 nm diameter are first prepared by self‐assembly in a poor solvent such as cyclohexanone, and then as‐prepared CdSe QDs are deposited compactly onto the P3HT nanowires by non‐covalent interactions between P3HT and CdSe. When illuminated with white light, the hybrid nanowires show enhanced photoconductivity compared with the pristine P3HT nanowires and the blended nanocomposites.
The synthesis of cationic mono‐(6‐O‐(1‐vinylimidazolium))‐ß‐cyclodextrin with toluenesulfonate as the corresponding anion is described. Free‐radical copolymerization of the resulting host–guest complex with N‐isopropylacrylamide or N,N‐diethylacrylamide yielded copolymers showing a temperature‐controlled solubility window in water. The impact of different anionic guests and salt concentrations on solubility behavior was investigated via turbidity measurements.
A novel pH‐responsive polymer vesicle obtained by the aqueous self‐assembly of carboxy‐terminated hyperbranched polyesters is reported. The synthesis is very simple, just a one‐step esterification of the commercially available hydroxy‐terminated hyperbranched polyester of Boltorn Hx (x = 20, 30, 40) with succinic anhydride. The vesicle size can be controlled from 200 nm to 10 µm by simply adjusting the solution pH as well as the degrees of branching (or generation).
Here, we show that a poly(ethylene oxide) polymer can be physically cross‐linked with silicate nanoparticles (Laponite) to yield highly extensible, bio‐nanocomposite fibers that, upon pulling, stretch to extreme lengths and crystallize polymer chains. We find that both, nanometer structures and mechanical properties of the fibers respond to mechanical deformation by exhibiting strain‐induced crystallization and high elongation. We explore the structural characteristics using X‐ray scattering and the mechanical properties of the dried fibers made from hydrogels in order to determine feasibility for eventual biomedical use and to map out directions for further materials development.
In this work, we design and synthesize a kind of amphiphilic mushroom cap‐shaped particles with wettability difference on the opposite sides of the particles. Colloidal crystals consisting of uniformly oriented anisotropic particles were fabricated on the water–air interface based on the wettability difference of particles. This simple approach offers a new way for self‐assembly of anisotropic colloidal crystal by amphiphilic design of particles.
A polymer system based on polydiacetylene (PDA) supramolecules that emits red, green, and blue fluorescence has been constructed. The three‐color emitting system is comprised of red‐fluorescent PDA vesicles in which green‐fluorescent fluorescein molecules are encapsulated. Finally, the blue‐fluorescence component is introduced by reacting terminal amine groups on the PDA vesicle surfaces with fluorescamine. Thin PDA‐polymer‐containing poly(vinyl alcohol) films formed by using this strategy display red, green, and blue fluorescence upon excitation with light at specific wavelengths.
A water‐soluble polymeric photosensitizer that contains naphthalene chromophores and absorbs light in the near UV region was obtained by modification of hydroxyethylcellulose. The excitation energy migrates along the naphthalene chromophores covalently attached to the polymer chain and can be used to induce photochemical reactions such as photoinduced electron transfer.
UV‐vis absorption (○), fluorescence emission (□), and fluorescence excitation (×) spectra of HENC in water at cHENC = 0.232 g/L, and (+) emission spectrum of the lamps used for irradiations. 相似文献
Summary: An amino‐functionalized bipyridine ligand was prepared in order to serve as a bridging unit to an activated low‐molecular‐weight monomethyl ether of poly(ethylene glycol) (PEG). Coordination of a ruthenium(II ) phenantroline precursor onto the formed PEG‐containing bipyridine ligand yielded a metal‐containing polymer which shows interesting properties for solar cell applications.
A schematic of the described polymeric ruthenium(II ) complex and its absorption and emission properties. 相似文献
Summary: The synthesis and thermal, redox and photoluminescence properties of a soluble donor‐acceptor polyplatinayne with the electron‐accepting silole ring and its model compound are described. The polymer has an optical band gap of 2.10 eV which is much lower than that of thienyl‐ or silyl‐bridged congeners. The incorporation of electron‐accepting silole unit in the metallopolymer main chain creates a new π‐conjugated system that features unique donor‐acceptor characteristics.
The design of responsive membranes whose interactions with inclusions can be controlled through the application of an external stimulus is reviewed with the aim to establish guidelines for introducing functionality into the materials. For a photo‐reactive AB membrane, we find that a gradient in light intensity can be harnessed to clean the system of any C “impurities”, or target the delivery of C to specific locations. By modeling the interactions between a lipid bilayer and Janus nanoparticles, we design a synthetic membrane with stable pores that can be controllably opened and closed. This leads to design rules for creating nanoparticle‐bilayer assemblies where the pores open and the cargo is released only when local environmental conditions reach a critical value.
A kinetic model of the amphiphilic star block copolymerization is developed. The star polymer species, resulting from star polymerization with dendrimer cores and hydrophobic monomers, are used as macroinitiators and initiate the graft polymerization of the hydrophilic monomers. Analytical expressions for the size distributions for the species formed in every step are derived. The method with monomers added to the reaction system in batches decreases the polydispersity index for the products obtained. It reaches a minimum if the monomer feed quantity is equal in every step. Therefore, the dimension and structure of the amphiphilic star block copolymers produced can be designed by using the proposed kinetic mechanism.
Summary: The success of metathesis chemistry techniques has sparked a tremendous interest in polymer and material chemistry. This contribution provides an overview of the state of the art in ring opening metathesis polymerisation (ROMP). It is intended to provide the reader with useful information on the interplay of initiators, monomers, and reaction conditions, thus aiding polymer chemists to utilise the ROMP toolbox. Prominent and illustrative examples from current research are given in the article.
We describe an enzyme‐responsive polymeric vehicle, which is of great interest in controlled drug delivery, biosensing, and other related areas. The polymer synthesized using lipase as catalyst in DMSO has a favorable molecular structure that is quickly hydrolyzed by lipase in aqueous phase, and allows a fast release of encapsulated molecules.
Herein we describe a novel and simple conjugated polymer‐fluorescent probe based platform for trypsin detection from protein mixtures in homogeneous solution. This platform takes advantage of specific interaction between the probe and the active site of trypsin and the electrostatic interaction between the polymer and the protein to mediate energy transfer between the polymer and the probe. This method does not require any separation steps, which should facilitate high‐throughput protease screening and drug discovery.
Summary: The synthesis of aqueous dispersions of hybrid acrylic copolymer particles with either a monofunctional or a multifunctional polyhedral oligomeric silsesquioxane methacrylate comonomer has been performed by free radical heterophase polymerization. The miniemulsion process gives stable latexes, whereas the less controlled emulsion route results in colloidal instability of the products. The thermal and mechanical properties of the nanocomposite latex films have been preliminarily investigated.
The nanocomposite latex particles based on hybrid copolyacrylates with highly dispersed POSS cages. 相似文献
