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Recent progresses in the developments of luminescent polymer films with stimuli responsiveness are illustrated. In particular, the influence of the alteration of connecting points in polymers on luminescent behaviors is explained. It is demonstrated that polymerization is a versatile strategy not only for transforming a class of nonemissive flexible boron complexes to luminescent dyes but also for precisely regulating optical properties of film materials that are promised to be applied as a scaffold for advanced chemical sensors.
A series of complexes consisting of natural amino acids and tin were developed as a new class of cost-effective catalysts with high reactivity and low toxicity towards some biocompatible aliphatic polyesters. The results demonstrated that Sn(AA)2 catalysts, especially the phenylalanine-tin complex (Sn(L-Phe)2) (Mn, up to 194 kg/mol), were suitable for the synthesis of moderate- and high-molecular-weight poly(L-lactide), which exhibited good biocompatibility.
The results of this investigation indicate that, compared with the high-molecular-weight amorphous polystyrene, the two low-molecular-weight amorphous polystyrenes studied herein have excess heat capacity below the glass-transition temperature. These results were obtained by analyzing the molecular vibrations of the high-molecular-weight polystyrene. The excitation energy obtained by regression analysis of the excess heat capacity determined by using the Schottky model is consistent with the excitation energy obtained by inelastic neutron scattering. This evidence strongly suggests that the excess heat capacity is due to vibrations of methyl end groups.
An efficient ambipolar organic transistor (A-OFET) based on the bilayer architecture of p-type poly(benzodithiophene(2-thienyl)-pyrrolopyrrole-dione) (PBDTTPPD) and n-type [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was demonstrated. The A-OFET exhibits clear bipolar transport and operates as an n-type and a p-type transistor in a single device.
Polypyrrole and poly(N-alkyl pyrrole) grains were synthesized by aqueous chemical oxidative polymerization in the presence of sodium dodecyl sulfate as both a dopant and a hydrophobizing agent. The dried polypyrrole and poly(N-ethyl pyrrole) grains showed hydrophobic character and can act as a light-responsive liquid marble stabilizer. Locomotion of the liquid marble can be driven by near-infrared laser irradiation-induced Marangoni flow on a planar air–water surface. Furthermore, the release of internal liquid can be achieved by controlled disruption of liquid marbles via external stimulus application.
Polylactide (PLA) formed an extended-chain crystal (ECC) and an extended-chain stereocomplex (ECSC) in Langmuir monolayers. Therefore, the chain packings in crystals and SCs could be identified by simply evaluating their sizes. A mixture of a high-molecular-weight (HMW) PDLA and a low-molecular-weight (LMW) PDLA was found to crystallize separately, while a mixture of an HMW-PLLA and an LMW-PDLA was found to form an SC composed of the extended LMW-PDLA chains and the folded HMW-PLLA chains. Furthermore, the molecular structure of SC was successfully visualized at the molecular level by AFM.
A series of polymeric hemostatic materials are prepared in one-step, by using biobased lactic acid monomers and mature hemostatic drugs (4-aminomethylbenzoic acid or tranexamic acid) through direct melt polycondensation. These materials are powdery with rough and irregular surfaces, and the powder particle size is ~8–30 μm, which is beneficial to the application, immediate hemostasis and scab-bionic membrane forming. Moreover, after the degradation of these materials at 37 °C, more monomers will be released, resulting in a higher efficiency and long-term hemostatic function.
We evaluated the biocompatibility and biodegradability of implants made of pure PLA and a PLA/PCL blend compatibilized with poly(ɛ-caprolactone-b-tetrahydrofuran) in horses by physical examination, plasma fibrinogen, thermographic, mechanical nociceptive threshold, and ultrasound tests. We also conducted histopathological and surface morphology analyses. Pure PLA and PLA/PCL blends subcutaneously implanted stimulated a minimal inflammatory response and supported cellular infiltration, being biocompatible and biodegradable in horses, with potential for use in equine medicine.
Cellulose nanofibers (CNFs) were utilized as nanofillers to improve mechanical properties of polysaccharide composite films made of polyion complexes (PICs) of chondroitin sulfate C (CS) and chitosan (CHI). Nonionic CNFs were homogeneously incorporated in the PIC gels, constructed by multiple electrostatic interactions, and the resulting free-standing films. The filler effects of CNFs were observed, especially in the Young’s modulus of the films in the wet state. Results indicated that CNFs in the films formed a rigid network structure with polysaccharides, contributing the reinforcement of the film strength.
The graphical abstract shows that the kinesin-driven quantum dot transport along microtubule immobilized on a substrate using glutaraldehyde concentration ≤0.10% (v/v) remain unaltered, whereas, at higher glutaraldehyde concentration, >0.10% (v/v), the quantum dot transportation is slowed down.
