Stimuli-Responsive Purely Organic Room-Temperature Phosphorescence Materials

This Minireview summarizes the recent progress of stimuli-responsive purely organic phosphorescence materials. Organic phosphorescence is closely related to the intermolecular interactions, because such interactions are beneficial to promote spin orbital coupling (SOC) and boost intersystem cross (ISC) efficiency and finally are conducive to satisfactory phosphorescence. It is found that the intermolecular interactions, which are essential for organic phosphorescence, are easily disturbed by external stimuli such as mechanical force, photon, acid, chemical vapor, leading to the luminescence change. According to this principle, various purely organic phosphorescence materials sensitive to external stimuli have been developed. This Minireview categorizes reported stimuli-responsive purely organic phosphorescence materials on the basis of different stimuli, including mechanochromism, mechanoluminescence, photoactivity, acid-responsiveness and other stimuli. Some prospective strategies for constructing stimuli-responsive purely organic phosphorescence molecules are provided.     

Porous shape memory polymers: Design and applications

Porous shape memory polymers (SMPs) exhibit geometric and volumetric shape change when actuated by an external stimulus and can be fabricated as foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. These materials have applications in multiple industries such as textiles, biomedical devices, tissue engineering, and aerospace. This review article examines recent developments in porous SMPs, with a focus on fabrication methods, methods of characterization, modes of actuation, and applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1300–1318     

Application Properties of Stimuli-Responsive Polyglycerol Hydrogels

Transient state swelling behavior and swelling kinetics of novel stimuli-responsive polyglycerol hydrogels were studied at 293, 310 and 333 K. Depending on temperature, Fickian or anomalous diffusion behavior was observed. Mechanical properties of the hydrogels in the swollen and dry states were investigated and the average molecular weight between crosslinks was calculated. To assess the potential for biodegradation of hydrogels, initial swelling behavior in phosphate buffered saline (PBS) solution and mass loss profiles as a function of degradation time were investigated over a period of 30 days. All swelling behavior, mechanical properties and degradations were clearly affected by the degree of cross-linking. The hydrophilicity and biodegradability of polyglycerol hydrogels make them suitable for pharmaceutical, biomedical and biotechnological applications. They could potentially serve as a substitute for common fossil-based hydrogels such as poly(ethylene glycol) and poly(vinyl alcohol) hydrogels.     

Responsive polymers for analytical applications: A review

Stimuli-responsive polymers are capable of translating changes in their local environment to changes in their chemical and/or physical properties. This ability allows stimuli-responsive polymers to be used for a wide range of applications. In this review, we highlight the analytical applications of stimuli-responsive polymers that have been published over the past few years with a focus on their applications in sensing/biosensing and separations. From this review, we hope to make clear that while the history of using stimuli-responsive polymers for analytical applications is rich, there are still a number of directions to explore and exciting advancements to be made in this flourishing field of research.     

偶氮苯基两亲性聚合物的自组装行为研究进展

偶氮苯基两亲性聚合物结合了偶氮苯基团的光响应、酶响应、主客体识别特性和两亲性聚合物的自组装特性,能够在选择性溶剂中发生聚合物可控自组装行为,这使得其在药物控释、纳米技术和生物医学材料等领域受到了广泛的关注。本文从结构类型和合成方法出发,综述了新型偶氮苯基两亲性聚合物在溶液中的自组装研究进展,并对该领域的发展前景进行了展望。     

Multiple Stimuli-Responsive Conformational Exchanges of Biphen[3]arene Macrocycle

Conformational exchanges of synthetic macrocyclic acceptors are rather fast, which is rarely studied in the absence of guests. Here, we report multiple stimuli-responsive conformational exchanges between two preexisting conformations of 2,2′,4,4′-tetramethoxyl biphen[3]arene (MeBP3) macrocycle. Structures of these two conformations are both observed in solid state, and characterized by ¹H NMR, ¹³C NMR and 2D NMR in solution. In particular, conformational exchanges can respond to solvents, temperatures, guest binding and acid/base addition. The current system may have a role to play in the construction of molecular switches and other stimuli-responsive systems.     

Polymer Nanocontainers for Intracellular Delivery

Carriers for intracellular delivery are required to overcome limitations of therapeutic agents such as low specificity, systemic toxicity, high clearance rate, and low therapeutic index. Nanocontainers comprised of an aqueous core and a polymer shell have received increasing attention because they readily combine stimuli response to improve intracellular payload release and surface modification to enhance selectivity towards the desired region of action. This Minireview summarizes the design and properties of polymer nanocontainers for intracellular delivery, classified according to the polymer architecture.     

Toward tunable and adaptable polymer nanocomposites

New bio-derived strategies have been recently explored in the design of polymer nanocomposites, particularly in the area of responsive materials, which offer pathways toward tailored interfacial adhesion, responsive interactions and controlled dispersion. In this Feature article, we discuss: (1) precise control of dispersion via self-assembly driven approaches in responsive mechanics, (2) inherent and strong interfacial adhesion in single polymer composites, and (3) percolating, electrospun nanofiber networks as filler elements in adaptable composites. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

双刺激响应型纳米载药系统的构建及性能

采用聚乙二醇单甲醚(mPEG)为亲水段,聚赖氨酸(PzLL)为疏水段,通过二硫键和碳氮双键串联桥连合成了两嵌段共聚物(mPEG-CN-SS-PzLL),其中的二硫键具有还原敏感性,碳氮双键具有pH酸敏感性。通过红外光谱和核磁共振谱等手段测试分析了产物的化学结构。将聚合物通过透析法自组装制备得到双刺激响应型纳米载药粒子。结果表明:该纳米载药粒子的药物包封率较高,达到52%。该载药系统在还原环境或酸性环境下具有良好的体外释药性能。