Design,synthesis and characterization of novel biodegradable macrodiols based on poly(DL-lactic acid) and poly(p-dioxanone)

Integrating poly（lactic acid） （PLA）, glycolic acid （GA） and ethylene glycol （EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone （PDO） was employed to copolymerize with DL-lactide （LA） via ring-opening melt polymerization using Sn（Oct）2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols （HO-P（LA-co-PDO）-OH） were just such a copolymer consisting of PLA, GA and EG. 1HNMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P（LA-co-PDO）-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P（LA-co-PDO）-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition, the molecular weights of HO-P（LA-co-PDO）-OH increased with decreasing PDO/LA ratios.

4天香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响

目的:探讨短期香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响。方法:BALB/c小鼠随机分为4组:对照组、熏烟组、poly(I:C)组和熏烟联合poly(I:C)组。检测支气管肺泡灌洗液(BALF)中总细胞数及细胞分类计数;普通光镜下观察各组细胞形态;荧光定量PCR检测肺组织细胞因子、趋化因子和干扰素及干扰素刺激基因表达。结果:与对照组相比,熏烟联合poly(I:C)组总细胞数计数、巨噬细胞与中性粒细胞计数明显升高(P<0.05),且熏烟联合poly(I:C)组巨噬细胞计数高于poly(I:C)组;与poly(I:C)组比较,熏烟联合poly(I:C)组小鼠气道灌洗液巨噬细胞体积较大,呈圆形或不规则形,细胞质较多空泡;与对照组相比,熏烟联合poly(I:C)组小鼠肺组织中性粒细胞趋化因子CXCL1(P<0.05)、CXCL2(P<0.01)和淋巴细胞趋化因子CCL2(P<0.01)mRNA表达升高,肺组织IL-1β、IL-6、TNF-αmRNA表达明显升高(P<0.01),肺组织IFN-β(P<0.01)、IFN-γ(P<0.05)、MX2(P<0.01)和IP-10(P<0.01)表达显著升高,且与poly(I:C)组小鼠相比,熏烟联合poly(I:C)组小鼠肺组织CXCL2(P<0.05)、TNF-α(P<0.01)和IFN-β(P<0.05)mRNA表达明显升高。结论:熏烟联合poly(I:C)诱导了小鼠肺部炎症反应和干扰素及干扰素刺激基因表达。同时,香烟暴露加剧了poly(I:C)诱导的小鼠肺部急性炎症反应和Ⅰ型干扰素表达。

Rapid synthesis of biodegradable poly(epsilon-caprolactone-co-p-dioxanone) random copolymers under microwave irradiation

Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO) random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL) and p-dioxanone(PDO) under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP) of PCDO have been discussed.The resultant products were characterized by ~1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In th...

Different crystallinity of poly(d,l-lactide-co-p-dioxanone) copolymers acquired by control of chain microstructure

Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.

Biodegradable Radiopaque Composite Filaments Based on Poly(p-dioxanone)and 2,3,5-triiodobenzoic Acid

To determine the possibility of blending 2, 3, 5-triiodobenzoic acid( TIBA) and poly( p-dioxanone)( PPDO) to produce X-ray visible PPDO filaments,melt-blended PPDO with different concentrations of TIBA was obtained. Several radiopaque filaments of PPDO polymer filled with radiopaque TIBA particles were prepared via melt-blending. Material properties of the composite filaments were investigated using various material characterization techniques,including scanning electron microscope( SEM),thermogravimetric analysis( TGA),X-ray Diffraction( XRD),dynamic rheometry and micro-CT scan. In this article,the dispersion of TIBA in PPDO,the properties of the filament,and the ratio of PPDO and TIBA and the corresponding X-ray visibility in vivo were studied. SEM results showed the dispersion of the contrast imaging agent TIBA was relatively even in the PPDO polymer. Xray analysis in vitro confirmed the enhanced radiopacity of the filaments with respect to the pure PPDO filament. The presence of iodine element in the composite filament could allow the bioabsorbable material to be monitored in vivo, and made it potential to be used in biomedical applications.

Enzymatic Synthesis and Characterization of Novel Amphiphilic Triblock Copolymer Poly(p-dioxanone-co-5-benzyloxytrimethylene carbonate)-block-poly(ethylene glycol)

Novel amphiphilic triblock copolymer poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）-block-poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate） （p（PDO-co-BTMC）-b-PEG-b-p（PDO-co-BTMC）） was successfully synthesized using immobilized porcine pancreas lipase on porous silica particles （IPPL） as the catalyst for the fLrSt time. 1H NMR, 13C NMR and GPC analysis were used to confirm the structures of resulting copolymers. The molecular weight （Mn） of the copolymer with feed ratio of 69：20：11 （BTMC： PDO： PEG ） was 31300 g/mol and the polydispersity was 1.85, while the Mn decreased to 25000 g/mol and polydispersity of 1.93 with the feed ratio of 50：40：10.

Innovative approach to boosting the chemical stability of AZ31 magnesium alloy using polymer-modified hybrid metal oxides

Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.

TOPCon太阳电池背面叠层poly工艺的优化及其对电性能的影响

通过增加TOPCon太阳电池poly层中的磷掺杂浓度可以增强poly层与硅基底之间的钝化效果并提高poly层与金属电极间的接触能力,但过高的掺杂浓度会导致磷原子扩散到硅基底,破坏氧化层与硅基底之间的界面钝化效果。为了解决这一问题,提出在poly层中间增加一层薄的氧化层作为阻挡层(即叠层poly工艺,下文简称为“叠层工艺”)的方案,将原本单一的poly-Si磷掺杂进行双层分布,底层poly-Si轻掺杂,表层poly-Si重掺杂;对常规工艺和叠层工艺制备TOPCon的太阳电池进行对比试验后,进一步优化叠层工艺,调整中间氧化层厚度,并研究不同中间氧化层厚度的叠层工艺对TOPCon太阳电池电性能的影响。实验结果表明:1)叠层工艺可以提高TOPCon太阳电池的电性能;2)当中间氧化层厚度提升至1.5 nm时,太阳电池的光电转换效率达到最高值(25.66%)。但中间氧化层的厚度是一个需要精确控制的工艺参数,需找到最佳的厚度平衡点,以提高太阳电池性能。

Flexible and Robust Functionalized Boron Nitride/Poly(p‑Phenylene Benzobisoxazole)Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation

With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.

A comparative study for petroleum removal capacities of the bacterial consortia entrapped in sodium alginate,sodium alginate/poly(vinyl alcohol),and bushnell haas agar

The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different polymers such as Sodium Alginate(SA),Sodium Alginate/Poly(Vinyl Alcohol)(SA/PVA),and Bushnell Haas Agar(BHA).In addition to SA and SA/PVA,which are cost-effective,non-toxic and have different functional groups,BHA,which is frequently encountered in laboratory-scale studies but has not been used as an entrapment material until now.Based on these,the polymers with different surface morphologies and chemical compositions were analyzed by SEM and FT-IR.While the petroleum removal efficiency was higher with the entrapped bacterial consortia than with the free one,BHA-entrapped bacterial consortium enhanced the petroleum removal more than SA and SA/PVA.Accordingly,the degradation rate of bacterial consortia entrapped with BHA was 2.039 day^(-1),SA/PVA was 1.560,SA was 0.993,the half-life period of BHA-entrapped bacterial consortia is quite low(t_(1/2)=0.339)compared with SA(t_(1/2)=0.444)and SA/PVA(t_(1/2)=0.697).The effects of the four main factors such as:amount of BHA(0.5,1,1.5,2,2.5,3 g),disc size(4,5,6,7,8 mm),inoculum concentration(1,2.5,5,7.5,10 mL),and incubation period on petroleum removal were also investigated.The maximum petroleum removal(94.5%)was obtained at≥2.5 mL of bacterial consortium entrapped in 2 g BHA with a 7 mm disc size at 168 h and the results were also confirmed by statistical analysis.Although a decrease was observed during the reuse of bacterial consortium entrapped in BHA,the petroleum removal was still above 50%at 10th cycle.Based on GC-MS analysis,the removal capacity of BHA-entrapped consortium was over 90%for short-chain n-alkanes and 80%for medium-chain n-alkanes.Overall,the obtained data are expected to provide a potential guideline in cleaning up the large-scale oil pollution in the future.Since there has been no similar study investigating petroleum removal with the bacterial consortia entrapped with BHA,this novel entrapment material can potentially be used in the treatment of petroleum pollution in advanced remediation studies.

High-performance and robust high-temperature polymer electrolyte membranes with moderate microphase separation by implementation of terphenyl-based polymers

Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(terphenyl piperidinium)s constructed from the m-and p-isomers of terphenyl were synthesized to regulate the microstructure of the membrane.Highly rigid p-terphenyl units prompt the formation of moderate PA aggregates,where the ion-pair interaction between piperidinium and biphosphate is reinforced,leading to a reduction in the plasticizing effect.As a result,there are trade-offs between the proton conductivity,mechanical strength,and PA retention of the membranes with varied m/p-isomer ratios.The designed PA-doped PTP-20m membrane exhibits superior ionic conductivity,good mechanical strength,and excellent PA retention over a wide range of temperature(80–160°C)as well as satisfactory resistance to harsh accelerated aging tests.As a result,the membrane presents a desirable combination of performance(1.462 W cm^(-2) under the H_(2)/O_(2)condition,which is 1.5 times higher than that of PBI-based membrane)and durability(300 h at 160°C and 0.2 A cm^(-2))in the fuel cell.The results of this study provide new insights that will guide molecular design from the perspective of microstructure to improve the performance and robustness of HT-PEMs.

Edaravone-loaded poly(amino acid) nanogel inhibits ferroptosis for neuroprotection in cerebral ischemia injury

Neurological injury caused by ischemic stroke is a major cause of permanent disability and death. The currently available neuroprotective drugs fail to achieve desired therapeutic efficacy mainly due to short circulation half-life and poor blood−brain barrier (BBB) permeability. For that, an edaravone-loaded pH/glutathione (pH/GSH) dual-responsive poly(amino acid) nanogel (NG/EDA) was developed to improve the neuroprotection of EDA. The nanogel was triggered by acidic and EDA-induced high-level GSH microenvironments, which enabled the selective and sustained release of EDA at the site of ischemic injury. NG/EDA exhibited a uniform sub-spherical morphology with a mean hydrodynamic diameter of 112.3 ± 8.2 nm. NG/EDA efficiently accumulated at the cerebral ischemic injury site of permanent middle cerebral artery occlusion (pMCAO) mice, showing an efficient BBB crossing feature. Notably, NG/EDA with 50 µM EDA significantly increased neuron survival (29.3%) following oxygen and glucose deprivation by inhibiting ferroptosis. In addition, administering NG/EDA for 7 d significantly reduced infarct volume to 22.2% ± 7.2% and decreased neurobehavioral scores from 9.0 ± 0.6 to 2.0 ± 0.8. Such a pH/GSH dual-responsive nanoplatform might provide a unique and promising modality for neuroprotection in ischemic stroke and other central nervous system diseases.

Systematic analysis of DNA polymerases as therapeutic targets in pan-cancers

Introduction:DNA polymerases are crucial for maintaining genome stability and influencing tumorigenesis.However,the clinical implications of DNA polymerases in tumorigenesis and their potential as anti-cancer therapy targets are not well understood.Methods:We conducted a systematic analysis using TCGA Pan-Cancer Atlas data and Gene Set Cancer Analysis results to examine the expression profiles of 15 DNA polymerases(POLYs)and their clinical correlations.We also evaluated the prognostic value of POLYs by analyzing their expression levels in relation to overall survival time(OS)using Kaplan-Meier survival curves.Additionally,we investigated the correlations between POLY expression and immune cells,DNA damage repair(DDR)pathways,and ubiquitination.Drug sensitivity analysis was performed to assess the relationship between POLY expression and drug response.Results:Our analysis revealed that 14 out of 15 POLYs exhibited significantly distinct expression patterns between tumor and normal samples across most cancer types,except for DNA nucleotidylexotransferase(DNTT).Specifically,POLD1 and POLE showed elevated expression in almost all cancers,while POLQ exhibited high expression levels in all cancer types.Some POLYs showed heightened expression in specific cancer subtypes,while others exhibited low expression.Kaplan-Meier survival curves demonstrated significant prognostic value of POLYs in multiple cancers,including PAAD,KIRC,and ACC.Cox analysis further validated these findings.Alteration patterns of POLYs varied significantly among different cancer types and were associated with poorer survival outcomes.Significant correlations were observed between the expression of POLY members and immune cells,DDR pathways,and ubiquitination.Drug sensitivity analysis indicated an inverse relationship between POLY expression and drug response.Conclusion:Our comprehensive study highlights the significant role of POLYs in cancer development and identifies them as promising prognostic and immunological biomarkers for various cancer types.Additionally,targeting POLYs therapeutically holds promise for tumor immunotherapy.

Application of the Shrinking Particle Model for the Evaluation of Molecular Recyclability of PET versus Semi-Aromatic Polyesters

The molecular recyclability of poly (ethylene terephthalate) (PET) and three semi-aromatic polyesters poly (phloretic acid) (poly-H), poly (dihydroferulic acid) (poly-G), and poly (dihydrosinapinic acid) (poly-S) is evaluated in this study. PET is an extensively used aromatic polyester, and poly-H, poly-G, and poly-S can be considered semi-aromatic poly (lactic acid) modifications. All these polyesters have been depolymerized at neutral pH and by acid- and base-catalyzed hydrolysis at two temperatures, i.e., 50˚C and 80˚C. Base-catalyzed depolymerization of virgin PET leads to an isolated yield of 38% after 48 hours of reaction at 80˚C. Contrary to these results for PET, almost all the monomers of the semi-aromatic polyesters poly-H, poly-G, and poly-S are recovered with isolated yields larger than 90% at the same temperature after 15 minutes in a facile manner. A shrinking particle model used to determine the global kinetics of the base-catalyzed depolymerization showed that the rate rises with increasing temperature. Using the shrinking particle model, the intrinsic reaction rate constants were determined. It has been demonstrated that the rate coefficients of the depolymerization of the semi-aromatic polyesters poly-H, poly-G, and poly-S are between 2 and 3 orders of magnitude higher than those for PET.

Novel sandwich structured glass fiber Cloth/Poly(ethylene oxide)-MXene composite electrolyte

Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

TOPCon太阳电池单面沉积Poly-Si的工艺研究

目前隧穿氧化层钝化接触(TOPCon)电池制造技术越来越成熟,所耗成本不断降低。行业内普遍采用低压化学气相沉积(LPCVD)方式进行双面沉积或单面沉积。单面沉积存在Poly-Si绕镀问题,严重影响电池片转化效率和外观质量,同时正面绕镀层去除难度较大,在用碱溶液去除绕镀层的同时,存在绕镀层去除不彻底或者非绕镀区域P^(+)层被腐蚀的风险,导致P^(+)发射极受损,严重影响电池片外观质量与性能。双面沉积可避免上述问题,但产能减少一半,制造成本增加。本文对单面沉积Poly-Si工艺及绕镀层去除工艺进行研究,在TOPCon电池正面及背面制作了一层合适厚度的氧化层掩膜,搭配合适的清洗工艺、去绕镀清洗工艺,既可有效地去除P^(+)层绕镀的Poly-Si,也可很好地保护正面P^(+)层及背面掺杂Poly-Si层不受破坏,同时可大幅提升产能。

Boosting thermal stability and crystallization of closed-loop-recyclable biodegradable poly(p-dioxanone) by end-group regulation

A chemically closed-loop-recyclable biodegradable polymer,poly(p-dioxanone)(PPDO),is one of the ideal candidates for single-use plastic products due to its suitability for different application scenarios.Fascinatingly,when PPDO wastes can be collected,its monomer p-dioxanone(PDO) will be obtained through chemical recycling of these wastes;when cannot be collected,the wastes are able to be biodegraded into harmless substances.However,unsatisfied thermal stability and low crystallization rate of PPDO restrict its wider applications.Herein,based on end-group regulation,we simultaneously realized the significant enhancement of thermal stability and crystallization of PPDO through the simple melt processing with tributyl phosphite(TBP) or triphenyl phosphite(TPP).The model reactions were conducted to investigate the reaction mechanism and theoretical products during the preparation of PPDO/phosphite compounds.Two kinds of phosphites were proved to act as the end-capped reagent and chain extender in the melt processing,while TBP presented better reactivity.As a result,the activation energy of thermal decomposition was largely elevated,and the unprecedented T_(5%)(the temperature at a weight loss of 5%) and Tmax(the temperature at a maximum rate of weight loss) of PPDO were obtained,i.e.,T_(5%)of ~330 ℃ and Tmaxof ~385 ℃ in N_(2) atmosphere,T_(5%)of ~240 ℃ and Tmaxof ~317 ℃ in air atmosphere,respectively.Furthermore,the increased crystallization rate,crystallinity,crystalline orderliness,and realizable monomer recovery(yield >90%,purity >99.9%) of PPDO/phosphite compounds were confirmed.

Poly(lactic acid)-aspirin microspheres prepared via the traditional and improved solvent evaporation methods and its application performances

Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, therefore a controllable delivery of aspirin is of importance to lighten those side effects. In this work, poly(lactic acid)(PLA) was chosen as the carrier to prepare PLA-aspirin microspheres by using the traditional and the improved solvent evaporation methods. It was found that no matter which experimental condition was, the encapsulation efficiency of aspirin was higher by using the improved method than that of the traditional method. Specifically, when the concentration of polyvinyl alcohol = 1%(mass),the polymer concentration = 1:20, the oil/water rate = 1:2.5, PLA-aspirin microspheres were obtained via the improved method with a high yield of 82.83%(mass) and an encapsulation efficiency of 44.09%. PLAaspirin microspheres were then prepared continuously using the improved method, which further enhanced the encapsulation efficiency to 54.56%. Approximate 85% aspirin released from microspheres within 7 days. Obvious degradation which was represented by reduction on hardness was observed by soaking microspheres in PBS for 60 days. This work is of interest because it provides a continuous route to prepare PLA-aspirin microspheres continuously with a high drug encapsulation efficiency.

Poly(ionic liquid)-crosslinked graphene oxide/carbon nanotube membranes as efficient solar steam generators

Graphene oxide(GO)is regarded as a promising candidate to construct solar absorbers for addressing freshwater crisis,but the easy delamination of GO in water poses a critical challenge for practical solar desalination.Herein,we improve the stability of GO membranes by a self-crosslinking poly(ionic liquid)(PIL)in a mild condition,which crosslinks neighbouring GO nanosheets without blemishing the hydrophilic structure of GO.By further adding carbon nanotubes(CNTs),the sandwiched GO/CNT@PIL(GCP)membrane displays a good stability in pH=1 or 13 solution even for 270 days.The molecular dynamics simulation results indicate that the generation of water nanofluidics in nanochannels of GO nanosheets remarkably reduces the water evaporation enthalpy in GCP membrane,compared to bulk water.Consequently,the GCP membrane exhibits a high evaporation rate(1.87 kg m^(-2)h^(-1))and displays stable evaporation rates for 14 h under 1 kW m^(-2)irradiation.The GCP membrane additionally works very well when using different water sources(e.g.,dye-polluted water)or even strong acidic solution(pH=1)or basic solution(pH=13).More importantly,through bundling pluralities of GCP membrane,an efficient solar desalination device is developed to produce drinkable water from seawater.The average daily drinkable water amount in sunny day is 10.1 kg m^(-2),which meets with the daily drinkable water needs of five adults.The high evaporation rate,long-time durability and good scalability make the GCP membrane an outstanding candidate for practical solar seawater desalination.

Electrospinning organic solvent resistant preoxidized poly(acrylonitrile)nanofiber membrane and its properties

A high performance preoxidized poly(acrylonitrile)(O-PAN)nanofiber membrane with excellent solvent resistance,thermal stability and flexibility was fabricated by the preoxidation of electrospun PAN nanofiber membrane.The performance of resultant O-PAN nanofiber membrane was optimized by altering the PAN concentration and preoxidation temperature.The results showed that the O-PAN nanofiber membrane which made from PAN concentration of 14%(mass)and preoxidation temperature of 250.0
℃ have a more optimal comprehensive performance.In the long-term separation test of SiO2 particle(1 μm)in DMAc suspension,the permeate flux of O-PAN nanofiber membrane stabilized at 227.91 L·m^(-2)·h^(-1)(25
℃,0.05 MPa)while the SiO2 rejection above 99.6%,which showed excellent solvent resistance and separation performance.In order to further explore the application of the O-PAN nanofiber membrane,the OPAN nanofiber membrane was treated with fluoride and used in oil/water separation process.The O-PAN nanofiber membrane after hydrophobic treatment showed excellent hydrophobicity and good oil/water separation performance with the permeate flux about 969.59 L·m^(-2)·h^(-1)while the separation efficiency above 96.1%.The O-PAN nanofiber membrane exhibited a potential application prospect in harsh environment separation.