Synthesis and Luminescent Property of Polycarbazole/Polyhedral Oligomeric Silsesquioxane Nanocomposites

Polyvinylcarbazole（PVK） composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane（POSS） PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature（Tg） in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% （mass fraction）, while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.

Study of Flame Retardation of Polycarbonate Modified by Polyhedral Oligomeric Silsesquioxane and Caged Bicyclic Phosphate

The flame-retarded polycarbonate（PC） has been made with octaphenyl polyhedral silsesquioxane（OPS） and/or caged bicyclic phosphate（Trimer）.Thermal gravimetric analysis（TGA）,Fourier-transform infrared（FTIR）,TGA-FTIR,limiting oxygen index（LOI）,and mechanical tests have been employed to characterize the modified PC.The additives of OPS and Trimer in PC have been proved to be effective flame-retardants because of the synergistic interaction between the elements of P and Si.The role of OPS and Trimer in PC degradation are different：OPS participates in the charring of PC,while Trimer makes PC degrade in advance.In addition,OPS and Trimer induced obvious differences in the mechanical properties of PC.

Fabrication of Layer-by-layer Films of Polyhedral Oligomeric Silsesquioxanes

Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled onto CaF2 slide to form nanocomposite multilayers. Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy. IR spectrum suggests existence of OSi8 and PDDA in the LBL films. Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology.

POSS基两亲性嵌段共聚物的合成及自组装行为

用不同结构三乙氧基硅烷为原料,通过水解缩合和环氧化的方法合成了环氧基苯基低聚笼型倍半硅氧烷,再利用胺基和环氧开环反应与聚醚胺反应合成POSS基嵌段共聚物(PEA-POSS),最后将苯基结构羧酸化合成两亲性嵌段共聚物(PEA-POSS-COOH)。利用傅里叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)表征了PEA-POSS-COOH的化学结构。采用溶剂挥发诱导法促使PEA-POSS-COOH自组装,形成以疏水POSS为核、亲水PEA链为壳的球形胶束。利用扫面电子显微镜(SEM)、能量分散型X射线光谱(EDS)、动态激光光散射(DLS)、小角X射线散射仪(XRD)和差示扫描量热仪(DSC)表征了组装体的形貌与结构性能。结果表明,POSS基两亲性嵌段聚合物可组装成粒径约1.14μm的球形胶束,且POSS结构中的π-π堆叠作用使得球形胶束具有较为稳定结构,熔点提高。

Bridged polyhedral oligomeric silsesquioxane(POSS):A potential member of silsesquioxanes

Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-capping＇ reaction.X-ray diffraction demonstrates that those two POSS have the similar T_8 structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.

Ultrasmall Nanoparticle ROS Scavengers Based on Polyhedral Oligomeric Silsesquioxanes

Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies.

Polymer solar cells with an inverted device configuration using polyhedral oligomeric silsesquioxane-[60]fullerene dyad as a novel electron acceptor

A polyhedral oligomeric silsesquioxane-[60]fullerene (POSS-C60) dyad was designed and used as a novel electron acceptor for bulk heterojunction (BHJ) polymer solar cells (PSCs) with an inverted device configuration. The studies of time-resolved photoinduced absorption of the pristine thin film of poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(4,7-bis (2-thienyl)-2,1,3-benzothiadiazole)-5,5'-diyl] (SiPCPDTBT) and the composite thin film of SiPCPDTBT:POSS-C60 indicated efficient electron transfer from SiPCPDTBT to POSS-C60 with inhibited back-transfer. BHJ PSCs made by SiPCPDTBT mixed with POSS-C60 yielded the power conversion efficiencies (PCEs) of 1.50%. Under the same operational conditions, PCEs observed from BHJ PSCs made by SiPCPDTBT mixed with [6,6]-phenyl-C61-butyric acid methyl ester were 0.92%. These results demonstrated that POSS-C60 is a potentially good electron acceptor for inverted BHJ PSCs.

Effectiveness of an ocular adhesive polyhedral oligomeric silsesquioxane hybrid thermo-responsive FK506 hydrogel in a murine model of dry eye

Dry eye is a common ocular disease that results in discomfort and impaired vision,impacting an individual’s quality of life.A great number of drugs administered in eye drops to treat dry eye are poorly soluble in water and are rapidly eliminated from the ocular surface,which limits their therapeutic effects.Therefore,it is imperative to design a novel drug delivery system that not only improves the water solubility of the drug but also prolongs its retention time on the ocular surface.Herein,we develop a copolymer from mono-functional POSS,PEG,and PPG(MPOSS-PEG-PPG,MPEP)that exhibits temperature-sensitive sol-gel transition behavior.This thermo-responsive hydrogel improves the water solubility of FK506 and simultaneously provides a mucoadhesive,long-acting ocular delivery system.In addition,the FK506-loaded POSS hydrogel possesses good biocompatibility and significantly improves adhesion to the ocular surface.In comparison with other FK506 formulations and the PEG-PPG-FK506(F127-FK506)hydrogel,this novel MPOSS-PEG-PPG-FK506(MPEP-FK506)hydrogel is a more effective treatment of dry eye in the murine dry eye model.Therefore,delivery of FK506 in this POSS hydrogel has the potential to prolong drug retention time on the ocular surface,which will improve its therapeutic efficacy in the management of dry eye.

Synthesis of peptide dendrimers with polyhedral oligomeric silsesquioxane cores via click chemistry

Inorganic polyhedral oligomeric silsesquioxane （POSS） was used as the core for the synthesis of poly（t- lysine） peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.

功能化POSS/磷酸共掺杂高温质子交换膜制备及其性能

为提高磷酸掺杂率,增强膜在高温低湿下的质子传导率,同时保证其机械性能,将季铵化八氨苯基笼型聚倍半硅氧烷(QOAPS)与溴甲基化聚芳醚酮和季铵化试剂三甲胺共混,得到含有QOAPS的季铵盐型聚芳醚酮铸膜液,并用流延法制备成膜,再以浸渍方式掺杂磷酸,获得功能化POSS/磷酸共掺杂型聚芳醚酮高温质子交换膜(PA-QPAEK@QOAPS).通过对不同QOAPS掺杂量的质子交换膜的磷酸掺杂量、尺寸稳定性、机械性能和质子传导率进行表征,表明功能化POSS的引入显著提高了膜的磷酸掺杂水平,在较高磷酸含量下,膜仍具有较好的机械强度以及尺寸稳定性.在180℃下,共掺杂型聚芳醚酮膜的质子传导率相较于原始季铵化聚芳醚酮膜提高了56%.

耐高温POSS基香料前体的制备及释香动力学研究

为研究耐高温香料前体在涤纶的芳香改性上的应用,以不同的香料醛分子和八(γ-氯氨丙基)多面体低聚倍半硅氧烷(OCAP-POSS)为原料,利用Schiff反应成功合成3种POSS基香料前体(M_(1)、M_(2)、M_(3))。采用核磁共振氢谱、红外光谱及紫外-可见光谱表征香料前体的结构;用热失重法研究香料前体的热稳定性能;此外,探索香料前体在模拟人体酸性汗液、中性及碱性皂液环境中的释香动力学特征。结果表明:3种香料前体的热分解温度都超过285℃,即香料前体具有良好的热稳定性;香料前体的结构对其释放性能有显著影响,M_(1)在酸性汗液环境下达到平衡时的释放率为57.86%,M_(3)却只有33.32%,且缓释时间M_(1)(29 h)>M_(2)(16 h)>M_(3)(12 h);3种香料前体在皂液环境下均较为稳定,在酸性汗液中可实现缓慢释放,其释放规律满足一级反应动力学特征。

Effect of Polyhedral Oligomeric Silsesquioxane and Sorbitol on Properties of Isotactic Polypropylene

Isotactic polypropylene（iPP） was modified by the introduction of polyhedral oligomeric silsesquioxanes（POSS） and 1,3：2,4-bis（3,4-dimethylbenzylidene）sorbitol（DMDBS）. Chemical combination of （3-mercapto）- propyl-heptaisobutyl POSS with DMDBS（POSS-DMDBS）, and physical mixing of DMDBS with octaisobutyl POSS （iso-POSS/DMDBS） or trisilanolisobutyl POSS（tri-POSS/DMDBS） were applied respectively to modifying iPP, and the effects of POSS and DMDBS on crystallization, rheological and mechanical properties of iPP were systematically investigated. The results indicate that iso-POSS/DMDBS and tri-POSS/DMDBS were more effective than POSS-DMDBS on the improvement of the crystallization behavior of iPP due to the higher crystallization temperature, while the crystal!inity of iPP containing POSS-DMDBS was enhanced, approximately approached to that of iPP containing tri-POSS/DMDBS. The tensile strength of iPP with POSS-DMDBS was significantly increased from 34 MPa to 40 MPa, as high as that of iPP with iso-POSS/DMDBS. The different effects caused by the specific interaction between POSS and DMDBS could possibly be applied in the modification of iPP.

Positive Luminescent Sensor for Aerobic Conditions Based on Polyhedral Oligomeric Silsesquioxane Networks

There are numerous numbers of hypoxia-selective luminescent probes based on oxygen quenching of phosphorescence.We show a unique design for luminescent probes to detect hyperoxia utilizing hybrid networks consisting of aggregation-induced emission(AIE)-active dyes and disulfide linkers.At the initial state,emission from the AIE-active dyes is inducible by suppressing energy-consumable intramolecular motions in the hybrid matrices,while the decrease in intensity was detected by releasing molecular motions corresponded to bond scission at the disulfide linkers.Particularly,it was shown that this process selectively proceeds in hypoxia.As a result,positive luminescent signals were obtained in hyperoxia.

Facile generation of highly durable thiol-functionalized polyhedral oligomeric silsesquioxane based superhydrophobic melamine foam

In this study,a durable superhydrophobic/superoleophilic melamine foam was fabricated by a facile and rapid one-step thiol-ene click chemistry and Michael addition reaction,which demonstrated excellent robustness in oil/water separation.First,1H,1H,2H-perfluoro-1-hexene reacted with thiol-functionalized polyhedral oligomeric silsesquioxane via the thiol-ene click chemistry to obtain a fluorinated thiol-functionalized polyhedral oligomeric silsesquioxane solution.Subsequently,the melamine foam was immersed to the solution system to form nanoaggregates on the melamine foam surface by the Michael addition reaction in the presence of ultraviolet light.The micro/nano rough structure and low surface energy of the nanoaggregates layer endowed the pristine melamine foam with superhydrophobicity;the water contact angle was greater than 150°.More importantly,the as-prepared melamine foam could withstand harsh conditions,such as a corrosive solution environment,strong ultraviolet light,mechanical compression,high and low temperature exposure,and ultrasonic washing.Driven by gravity,the as-prepared melamine foam could efficiently separate the oil/water mixtures and maintain 98%separation efficiency at high and low temperatures.In addition,it maintained the desirable absorption capability in different oil/organic solvents even after 15 absorption cycles.Accordingly,this facile,low-cost,and robust onestep method provides important support for the superhydrophobic oil/water separation field.

POSS改性邻苯二甲腈树脂制备及性能

为探究不同结构笼型聚倍半硅氧烷(POSS)对邻苯二甲腈(PN)树脂综合性能的影响,以PN树脂为基体,分别添加了三硅烷醇苯基POSS、氨基丙基异丁基POSS、缩水甘油基异丁基POSS、三硅醇异丁基POSS及环氧环己基异丁基POSS 5种POSS,利用溶液共混法制备了改性PN浇铸体试样,并制备了PN/石英布复合材料。开展了热重分析、动态热机械分析、透波率测试、介电性能测试等多种试验,研究了不同结构POSS对PN树脂热稳定性以及复合材料透波性能和介电性能的影响。结果表明,POSS的引入提升了PN树脂的耐热性能及热分解起始温度,同时,POSS的引入提高了PN树脂的玻璃化转变温度,提高了材料的可用温度范围,也提升了PN复合材料在12~18 GHz及26.5~40 GHz两个波段下的透波性能。除环氧环己基异丁基POSS使PN复合材料的介电损耗有所增大外,其余4种POSS对复合材料的介电性能影响较小。综合分析5种改性后的试样表明,使用三硅醇异丁基POSS改性的PN树脂及复合材料具有最优的综合性能。该改性PN复合材料在12~18 GHZ频率下的平均透波率可达74.21%,在26.5~40 GHz频率下的平均透波率可达76.55%,玻璃化转变温度可达378.5℃,并且在氮气环境下的热分解起始温度达到了515.1℃,且介电性能相对未改性变化不大,是一种优异的耐高温透波材料。

POSS在生物医药领域的应用研究进展

多面体低聚倍半硅氧烷(POSS)是纳米级的倍半硅氧烷分子,由于其独特的中空笼型结构,作为有机无机杂化纳米材料在医药领域的应用备受关注。本文主要就近年来POSS在药物递送系统、组织工程支架及造影成像等方面的应用进行综述。

六面体倍半硅氧烷(POSS)杂化材料

POSS作为一种新型的有机/无机杂化材料在近10年的研究中引起了人们的极大关注,这种杂化材料可以通过不同的合成方法获得,为材料的设计提供了极大的便利。本文综述了近几年来POSS基有机/无机杂化的电致发光材料、液晶材料和POSS衍生物的自组装行为的研究进展,指出这类材料由于制作方便和热力学性能优良,在未来高科技领域中必有宽广的应用前景。

聚硅氧烷-聚酰亚胺复合材料抗原子氧侵蚀机理分子动力学研究

为了探究不同取代基聚硅氧烷提升聚酰亚胺在太空环境中抵抗原子氧(AO)侵蚀能力的作用机制,本研究采用反应分子动力学(MD)模拟,分析了取代基分别为三氟甲基(-CF_(3))和甲基(-CH_(3))的多面体笼型聚硅氧烷(POSS)复合聚酰亚胺纳米材料的抗原子氧侵蚀性能。结果表明:PI/CH_(3)-POSS和PI/CF_(3)-POSS复合材料均表现出较强的抗AO侵蚀能力,其作用机制是通过形成SiO_(2)层以阻止AO向聚合物基体的传播和热量的传递,其中PI/CF_(3)-POSS复合材料的效果最优,经35 ps的AO侵蚀模拟后其归一化质量为0.83,而PI/CH_(3)-POSS复合材料的归一化质量为0.78。

聚乙烯咪唑/POSS纳米复合质子导电材料的制备与性能研究

研究制备了一种新型基于化学键合的聚乙烯咪唑/POSS纳米复合材料(POSS-b-PVI),并获得一种基于POSS-b-PVI的磷酸掺杂高温非水体系的质子导电膜。研究表明:与纯聚乙烯咪唑薄膜相比,该纳米复合质子导电材料的可见光透过率和质子导电率等有大幅度的提高,在200℃条件下该纳米复合质子导电材料的导电率可以达到7×10-4S/cm,光学透过率可达32%。

POSS聚合物及其新进展

POSS作为一种特殊的有机/无机杂化纳米构件备受关注。本文总结了近几年有关探索POSS聚合物结构与性能之间关系的研究进展,并重点综述了POSS在有机半导体材料领域的应用。