In-situ photocrosslinked hydroxide conductive membranes based on photosensitive poly(arylene ether sulfone) block copolymers for anion exchange membrane fuel cells

He, Rui,Wen, Pushan,Zhang, Hai-Ning,Guan, Shumeng,Xie, Guangyong,Li, Li-Zhong,Lee, Myong-Hoon,Li, Xiang-Dan Elsevier 2018 Journal of membrane science Vol.556 No.-

<P><B>Abstract</B></P> <P>A series of photocrosslinkable multi-block poly(arylene ether sulfone) copolymers containing various block lengths of hydrophilic segments were synthesized. For comparison, a series of random poly(arylene ether) copolymers were also synthesized. The anion exchange membranes(AEMs) were fabricated and in-situ photocrosslinking was carried out by UV irradiation in a swollen state. The microphase-separated morphologies of the multi-block membranes were characterized by SAXS and TEM experiments, and the membrane properties were investigated by measuring ion exchange capacity (IEC), water uptake, water swelling ratio, ionic conductivity, methanol permeability and alkaline stability. IECs and water uptakes of the crosslinked multi-block membranes were in the range of 1.11–1.42 meq g<SUP>−1</SUP> and 14.36–31.01% at 20 °C, respectively. The hydroxide conductivity was in the range of 11.38–25.00 mS cm<SUP>−1</SUP> at 20 °C, and showed a maximum value of 178.77 mS cm<SUP>−1</SUP> at 100 °C. The multi-block membranes exhibited low methanol permeability (2.75 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>) at room temperature, which is one order of magnitude lower than that of Nafion® 117 (23.8 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>). The crosslinked membranes showed excellent dimensional stability and alkaline stability with only a slight decrease in ionic conductivity. All the multi-block membranes showed superior properties compared to their corresponding random copolymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multi-block poly(arylene ether sulfone) copolymers were synthesized for AEMs. </LI> <LI> <I>In-situ</I> photo-crosslinking was carried out by UV irradiation in hydrated states. </LI> <LI> The block copolymers exhibited hydrophilic/hydrophobic phase separated morphology. </LI> <LI> The block copolymers showed superior properties compare to the random copolymers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

NiCo₂O₄ nanostructure-decorated PAN/lignin based carbon nanofiber electrodes with excellent cyclability for flexible hybrid supercapacitors

Lei, Danyun,Li, Xiang-Dan,Seo, Min-Kang,Khil, Myung-Seob,Kim, Hak-Yong,Kim, Byoung-Suhk Elsevier 2017 Polymer Vol.132 No.-

<P><B>Abstract</B></P> <P>Nanostructured binary metal oxide-decorated carbon nanofibers (CNFs) were utilized as flexible electrodes for hybrid supercapacitor applications. Polyacrylonitrile (PAN)/lignin based carbon nanofibers (PAN/lignin CNFs) with different contents of lignin were prepared by electrospinning, stabilization and carbonization. Afterwards, the NiCo<SUB>2</SUB>O<SUB>4</SUB> oxides were deposited on the surface of CNFs by a facile hydrothermal method without any toxic reagents. SEM images confirmed that the NiCo<SUB>2</SUB>O<SUB>4</SUB> (nanosheet and nanoneedle) nanostructures were uniformly grown on the surface of every carbon fiber. The obtained flexible NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated PAN/lignin CNFs with 50% lignin (NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNF55) electrode exhibited high specific capacitance of the ∼1757 F g<SUP>−1</SUP> at 2 mA cm<SUP>−2</SUP> and excellent cyclability with ∼138% capacitance retention after 5000 cycles at 7 mA cm<SUP>−2</SUP>, suggesting lower internal resistance and higher electrochemical reversibility. In addition, the NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNFs//N-rGO solid state asymmetric supercapacitor devices were assembled in order to evaluate their practical applications. The NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNF55//N-rGO asymmetric supercapacitor device exhibited a specific capacitance of 134.3 F g<SUP>−1</SUP> at a current densities of 1 A g<SUP>−1</SUP>, and possessed a maximum energy density of 47.75 Wh kg<SUP>−1</SUP> with a power density of 799.53 W kg<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PAN/lignin-based carbon fibers were prepared by electrospinning, stabilization and carbonization. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB> nanostructures were fabricated on PAN/lignin-based carbon nanofibers. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated fiber electrode exhibits highest specific capacitance of the ∼1757 Fg<SUP>-1</SUP>. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated fiber electrode shows excellent capacitance retention of ∼138% after 5000 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Syntheses and characterizations of high refractive index and low birefringence polyimides containing spirobifluorene in the side chain

Wen, Pushan,He, Rui,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2017 Polymer Vol.117 No.-

<P><B>Abstract</B></P> <P>Two new diamine monomers having a spirobifluorene structure were synthesized through four steps, and polymerized with three different dianhydrides (PMDA, CBDA and 6FDA) to obtain six polyimides with spirobifluorene structure in the side chain. All the resulting polyimides displayed excellent thermal stability and high glass transition temperature. These polyimides synthesized from CBDA and 6FDA showed good solubility in typical organic solvents such as NMP, DMF and DMSO. Transparent and flexible cast films can be obtained from soluble polyimides or poly(amic acid) solution. The transmittance of polyimide films was higher than 90% in the visible wavelength range (higher than 80% in case of polyimide containing PMDA). The refractive indices of the result polyimides were found to be in the range from 1.6343 to 1.7007, which is higher than that of normal polymers. In addition, the optical birefringences of these polyimides were extremely low (0.0005–0.0014). The high refractive index and low birefringence of these polyimides as well as other descent physical and thermal properties would offer them possible applications in high performance optical materials such as flexible substrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel polyimides containing 9,9’-spirobifluorene unit in the side chain were synthesized. </LI> <LI> The polyimides exhibit high thermal stability (T5 > 420 °C) with excellent optical properties such as high transparency (>90% at 400 nm), high refractive index (1.6342–1.7007) and low birefringence (0.0005–0.0014). </LI> <LI> The resulting polymer materials could be promising candidates for advanced optical applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Novel polyimides containing 9,9′-spirobifluorene unit in the side chain, which exhibit high transparency, high refractive index and low birefringence, have been developed as promising candidates for advanced optical applications.</P> <P>[DISPLAY OMISSION]</P>

Fabrication of highly efficient coatable polarizer from tolane-based smectic reactive mesogen

He, Rui,Oh, Enche,Ye, Yang,Wen, Pushan,Jeong, Kwang-Un,Lee, Seung Hee,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2019 Polymer Vol.176 No.-

<P><B>Abstract</B></P> <P>This work is aimed to fabricate ultra-thin coatable polarizers on a single substrate based on “host-guest” effect between highly ordered smectic reactive mesogen (RM) and dichroic dye. We designed and synthesized a new tolane-based RM with a highly ordered smectic A phase at room temperature. Polymerizable “host-guest” mixture was formulated from the host RM, dichroic dye and additives, then spin-coated on a single substrate having an alignment layer. Subsequent in-situ photopolymerization by UV irradiation successfully resulted in a coatable polarizer with good polarizing properties. The fabricated coatable polarizer showed a dichroic ratio (DR) of 16.4 and a degree of polarization (DOP) of 99.3% with the thickness of 4 μm. The resulting coatable polarizer possessed a considerable solvent resistance, good thermal stability and robust mechanical properties. Moreover, we prepared a TN-mode LC cell by using the prepared coatable polarizers inside the cell (in-cell), in which the coatable polarizers acted as a polarizer and an alignment layer, simultaneously. The resulting TN cell with in-cell polarizers exhibited a decent electro-optical behavior. We believe that the coatable polarizer proposed in this study possesses practical application potential in ultra-thin LCDs or flexible OLEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Reactive mesogen with smectic A phase was synthesized for coatable polarizer. </LI> <LI> Coatable polarizer was fabricated on a single substrate by “host-guest” method. </LI> <LI> Coatable polarizer exhibits considerable optical property and excellent stability. </LI> <LI> LCD with in-cell structure was demonstrated by using the prepared coatable polarizer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of Pre-carbonization Temperature on the Properties of Plasticized Spinning Polyacrylonitrile Fibers

Xiang Li,Zhaoling Li,Xiaonan Dang,Dan Luan,Feng Wang 한국섬유공학회 2018 Fibers and polymers Vol.19 No.3

In this work, plasticized spinning PAN fibers were treated at low carbonization temperature for the first time. The properties of treated fibers were characterized by elemental analysis (EA), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) respectively. The SEM results show that cross section of the pre-carbonized fibers is circular with no apparent skin-core structure. During the pre-carbonization process (320-380 oC), fracture mode of the fibers gradually changes from ductile to brittle and fibril diameter gradually decreases. Pre-carbonization temperature at 350 oC significantly accelerates chemical reactions. The FTIR results show that a stable oxygen structure is generated as treated at 320 oC.

Liquid Crystal Photoalignment by Soluble Photosensitive Polyimide with Methylene Cinnamate Side Units

Li Xiang-Dan,Zhong Zhen-Xin,Jin Guang,Lee Seung-Hee,Lee Myong-Hoon The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.3

Fibulin2: a negative regulator of BMSC osteogenic differentiation in infected bone fracture healing

Li Shi-Dan,Xing Wei,Wang Shao-Chuan,Li You-Bin,Jiang Hao,Zheng Han-Xuan,Li Xiao-Ming,Yang Jing,Guo De-Bin,Xie Xiao-Yu,Jiang Ren-Qing,Fan Chao,Li Lei,Xu Xiang,Fei Jun 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Bone fracture remains a common occurrence, with a population-weighted incidence of approximately 3.21 per 1000. In addition, approximately 2% to 50% of patients with skeletal fractures will develop an infection, one of the causes of disordered bone healing. Dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays a key role in disordered bone repair. However, the specific mechanisms underlying BMSC dysfunction caused by bone infection are largely unknown. In this study, we discovered that Fibulin2 expression was upregulated in infected bone tissues and that BMSCs were the source of infection-induced Fibulin2. Importantly, Fibulin2 knockout accelerated mineralized bone formation during skeletal development and inhibited inflammatory bone resorption. We demonstrated that Fibulin2 suppressed BMSC osteogenic differentiation by binding to Notch2 and inactivating the Notch2 signaling pathway. Moreover, Fibulin2 knockdown restored Notch2 pathway activation and promoted BMSC osteogenesis; these outcomes were abolished by DAPT, a Notch inhibitor. Furthermore, transplanted Fibulin2 knockdown BMSCs displayed better bone repair potential in vivo. Altogether, Fibulin2 is a negative regulator of BMSC osteogenic differentiation that inhibits osteogenesis by inactivating the Notch2 signaling pathway in infected bone.

Liquid Crystal Photoalignment by Soluble Photosensitive Polyimide with Methylene Cinnamate Side Units

Xiang Dan Li,Zhen Xin Zhong,Guang Jin,Seung Hee Lee,Myong Hoon Lee 한국고분자학회 2006 Macromolecular Research Vol.14 No.3

Efficacy of Prophylactic Entecavir for Hepatitis B Virus-Related Hepatocellular Carcinoma Receiving Transcatheter Arterial Chemoembolization

Li, Xing,Zhong, Xiang,Chen, Zhan-Hong,Wang, Tian-Tian,Ma, Xiao-Kun,Xing, Yan-Fang,Wu, Dong-Hao,Dong, Min,Chen, Jie,Ruan, Dan-Yun,Lin, Ze-Xiao,Wen, Jing-Yun,Wei, Li,Wu, Xiang-Yuan,Lin, Qu Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Background and Aims: Hepatitis B virus (HBV) reactivation was reported to be induced by transcatheter arterial chemoembolization (TACE) in HBV-related hepatocellular carcinonma (HCC) patients with a high incidence. The effective strategy to reduce hepatitis flares due to HBV reactivation in this specific group of patients was limited to lamivudine. This retrospective study was aimed to investigate the efficacy of prophylactic entecavir in HCC patients receiving TACE. Methods: A consecutive series of 191 HBV-related HCC patients receiving TACE were analyzed including 44 patients received prophylactic entecavir. Virologic events, defined as an increase in serum HBV DNA level to more than 1 log10 copies/ml higher than nadir the level, and hepatitis flares due to HBV reactivation were the main endpoints. Results: Patients with or without prophylactic were similar in host factors and the majorities of characteristics regarding to tumor factors, HBV status, liver function and LMR. Notably, cycles of TACE were parallel between the groups. Ten (22.7%) patients receiving prophylactic entecavir reached virologic response. The patients receiving prophylactic entecavir presented significantly reduced virologic events (6.8% vs 54.4%, p=0.000) and hepatitis flares due to HBV reactivation (0.0% vs 11.6%, p=0.039) compared with patients without prophylaxis. Kaplan-Meier analysis illustrated that the patients in the entecavir group presented significantly improved virologic events free survival (p=0.000) and hepatitis flare free survival (p=0.017). Female and Eastern Cooperative Oncology Group (ECOG) performance status 2 was the only significant predictors for virological events in patients without prophylactic antiviral. Rescue antiviral therapy did not reduce the incidence of hepatitis flares due to HBV reactivation. Conclusion: Prophylactic entecavir presented promising efficacy in HBV-related cancer patients receiving TACE. Lower performance status and female gender might be the predictors for HBV reactivation in these patients.

Hepatitis B Virus DNA Negativity Acts as a Favorable Prognostic Factor in Hepatocellular Carcinoma Patients

Li, Xing,Zhong, Xiang,Chen, Zhan-Hong,Xing, Yan-Fang,Wu, Dong-Hao,Chen, Jie,Ma, Xiao-Kun,Lin, Qu,Wen, Jing-Yun,Wei, Li,Wang, Tian-Tian,Ruan, Dan-Yun,Lin, Ze-Xiao,Wu, Xiang-Yuan,Dong, Min Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: This retrospective study was aimed to investigate the efficacy of prophylactic agents in hepatocellular carcinoma (HCC) patients receiving TACE and compare the difference between lamivudine and entecavir. Materials and Methods: A consecutive series of 203 HBV-related HCC patients receiving TACE were analyzed including 91 patients given prophylactic agents. Virologic events, defined as an increase in serum HBV DNA level to more than 1 log10 IU/ml higher than the nadir level, hepatitis flares due to HBV reactivation and progression free survival (PFS) were the main endpoints. Results: Some 48 (69.6%) reached virologic response. Prophylaxis significantly reduced virologic events (8.8% vs 58.0%, p=0.000) and hepatitis flares (1.1% vs 13.4%, p=0.001). Patients presenting undetectable HBV DNA levels displayed a significantly improved PFS as compared to those who never achieved undetectable HBV DNA. Prophylaxis and e-antigen positivity were the only significant variables associated with virologic events. In addition, prophylaxis was the only independent protective factor for hepatitis flares. Liver cirrhosis, more cycles of TACE, HBV DNA negativity, a lower Cancer of the Liver Italian Program score, non-metastasis and no hepatitis flares were protective factors for PFS. Prophylactic lamivudine demonstrated similar efficacy as entecavir. Conclusions: Prophylactic agents are efficacious for prevention of HBV reactivation in HCC patients receiving TACE. Achievement of undetectable HBV DNA levels displayed a significant capability in improving PFS. Moreover, persistent tumor residual lesions, positive HBV DNA and hepatitis B flares might be causes of tumor progression in these patients.