检索结果-南通市图书馆

SYNTHESIS OF NOVEL LIQUID CRYSTALLINE POLY(METH)ACRYLATES CONTAINING SILOXANE SPACER AND TERPHENYLENE MESOGENIC UNIT

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of polymer science 2000年第2期18卷 101-107页

作者： zhi-qian Zang Yu-fei Luo Dong zhang Xin-hua Wan Qi-feng Zhou department of polymer science & engineering, college of chemistry, peking university, beijing 100871, china 北京大学北京

Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4 '-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxane moiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC, DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase. However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results also showed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporated to obtain the highest possible decoupling effect.

关键词： liquid crystalline polymers polyacrylates 4 ''-cyano-p-terphenyl

SYNTHESIS AND PROPERTIES OF A NEW AZOBENZENE SIDE-CHAIN polymer CONTAINING A TEMPO RADICAL

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of polymer science 2002年第4期20卷 285-290页

作者： Yong zhang Ze-da Xu Xing-he Fan Xiao-fang Chen Xin-hua Wan Qi-feng Zhou department of polymer science and engineering college of chemistry and molecular engineering peking university, beijing 100871, china department of polymer science and engineering College of Chemistry and Molecular Engineering Peking University 北京 100871

To allow anisotropies of optical properties in a magnetic field, nitroxide radical is introduced into the ortho-position of the phenylene ring in the side chain. A new azobenzene side-chain polymer (TEMPO-PAZ) containing TEMPO radical was synthesized. The polymer has a good solubility in organic solvents. The ESR spectrum of the polymer indicated three absorption lines characteristic of TEMPO radical. The optical phase conjugated responses (I-4) of the polymer films were investigated by degenerate four-wave mixing (DFWM). The experimental results showed that optical phase conjugated response of the TEMPO-PAZ could be easily controlled by choosing the appropriate direction of magnetic field presumably due to the nitroxide radical in the TEMPO-PAZ molecular structure. For the polymer investigated here, the nitroxide radical was introduced to increase optical phase conjugated response intensity in a magnetic field, aiming originally at searching for a new photo-active organic magnetic multifunctional materials.

关键词： azobenzene nitroxide radical polymer photo-active organic magnetic materials optical phase conjugated responses

NITROXIDE-MEDIATED FREE RADICAL SYNTHESIS OF MESOGEN-JACKETED LIQUID CRYSTAL polymerS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of polymer science 1999年第2期17卷 189-192页

作者： Xin-hua Wan Hui-lin Tu Ying-feng Tu Dong zhang Ling Sun Qi-feng Zhou Yu-ping Dong Mao Tang department of polymer science & engineering, college of chemistry, peking university, beijing 100871, china department of Materials & Chemical engineering, beijing Institute of Technology, beijing 100081, china 北京大学化学院北京 100871 北京大学化学院北京北京理工大学材料化学工程系北京 100081 北京理工大学材料化学工程系北京

The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.

关键词： TEMPO 'living' free radical polymerization mesogen-jacketed liquid crystal polymer mesophase polymerization

Ordered Bicontinuous Network Structures Regulated by Orientational Interactions in a Rod-Coil Block Copolymer

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of polymer science 2024年第5期42卷 636-642,I0008页

作者： Xiao-Lin Lyu Shi-Chu Yang An-Qi Xiao Ping-Ping Hou Wei zhang hong-Bing Pan zhi-Hao Shen Xing-He Fan Qi-Feng Zhou beijing National Laboratory for molecular sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Key Laboratory of Advanced Materials Technologies International(HongKong Macao and Taiwan)Joint Laboratory on Advanced Materials TechnologiesCollege of Materials Science and EngineeringFuzhou UniversityFuzhou350108China

The rich phase behavior of block copolymers(BCPs)has drawn great attention in recent ***,the double diamond(DD)phase is rarely obtained because of the competition between the minimization of interfacial energy and packing ***,a rod-coil BCP containing mesogen-jacketed liquid crystalline polymer is designed to acquire ordered bicontinuous network *** reduction of internal energy originating from the orientational interaction among the rod blocks can compensate for the free energy penalty of packing frustration to stabilize the DD *** resulting BCP can also experience lamellae-to-DD and double gyroid-to-lamellae transitions by changing the annealing *** results make the rod-coil BCP an excellent candidate for the self-assembly of ordered network structures,demonstrating great potential in nanopatterning and metamaterials.

关键词： Block copolymer Rod-coil Ordered bicontinuous phase Double diamond Double gyroid

Distinguishing malignant from normal stomach tissues and its in vivo, in situ measurement in operating process using FTIR Fiber-Optic techniques

在线全文

学校读者我要写书评

暂无评论

science china chemistry 2005年第2期48卷 167-175页

作者： XU Yizhuang1, YANG Limin1, XU zhi3, ZHAO Ying2, LING Xiaofeng3, LI Qingbo1, WANG Jiansheng4, zhang Nengwei3, zhang Yuanfu1 & WU Jinguang1 1. The State Key Laboratory of Rare Earth Materials and Applications, college of chemistry and molecular engineering, peking university, beijing 100871, china 2. Institute of chemistry, Chinese Academy of sciences, beijing 100080, china 3. department of Surgery, Third Hospital, peking university, beijing 100083, china 4. department of Oncology Surgery, the First Hospital of Xi’an Jiaotong university, Xi’an 710061, china Correspondence should be addressed to Wu Jinguang (email: wujg@***) The State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing China department of Surgery Third Hospital Peking University Beijing China Institute of chemistry Chinese Academy of Sciences Beijing China department of Oncology Surgery the First Hospital of Xi’an Jiaotong University Xi’an China

Gastric tissue samples were studied using mid-IR fiber-optic attenuated total reflectance (ATR) spectroscopy. FTIR spectra of 90 tissue samples from 48 patients, including 32 normal and 58 malignant tissue samples, were chosen as examples. Malignancy was usually characterized by the absence of CH and C=O bands, a weak amide II band near 1545 cm-1, a shift of the amide I band to lower wave number, a decrease in the ～1450 cm-1 peak to less than the～1400 cm-1 peak. Subtraction spectra indicate that the amide I and amide II bands of normal and malignant tissues have larger differences in peak positions and relative intensities. The statistical analysis results confirm this conclusion. The results indicate that FTIR fiber optic techniques provide important information about cancerous tissue of the stomach, which can be used to differentiate the malignant tissue from the normal tissue. Based on the above results we successfully realize the detection of the tumor tissues of digestive tract in vivo and in situ. And the results of detection cancer near operating room and in vivo and in situ in the operating room are consistent with the conclusions for the samples stored in liquid N2, which is the basis for the clinical application.

关键词： FTIR, Fiber-Optics, stomach tissues, cancer, diagnosis.

DEGRADABLE THERMORESPONSIVE POLYESTERS BY ATOM TRANSFER RADICAL POLYADDITION AND CLICK chemistry

在线全文

学校读者我要写书评

暂无评论

DEGRADABLE THERMORESPONSIVE POLYESTERS BY ATOM TRANSFER RADI...

Tunable Phase Structure of Side-chain Liquid Crystalline polymers Enabled by molecular engineering of Dual Mesogenic Cores

第五届国际高分子化学学术讨论会

作者： Li-Jing zhang Bo-Tao Dong Fu-Sheng Du and Zi-Chen Li beijing National Laboratory for molecular sciences(BNLMS) Key Laboratory of polymer chemistry& Physics of Ministry of Education department of polymer science&engineering college of chemistry and molecular engineering peking university beijing 100871 china.

＜正＞LCST-type thermoresponsive polymers have found a variety of applications in biomedical science ranging from smart surfaces,bio-sensing and tissue engineering to intelligent drug/gene delivery.1 However,as most of the above polymers are based on carbon-carbon backbone,the non-degradability may limit their in vivo

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Journal of polymer science 2024年第10期42卷 1459-1469,I0009页

作者： Wen-Huan Yao Lan-Sheng Liu Jie Zhao Yan-Xia Wang An-zhi Ma Zheng-Rui Ma Lan-Ying zhang Ruo-Chen Lan college of chemistry and Chemical engineering Hunan UniversityChangsha410082China Key Laboratory of Eco-Functional polymer Materials of the Ministry of Education Key Laboratory of Eco-Environmental Polymer Materials of Gansu ProvinceCollege of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou730070China department of Materials science and engineering College of EngineeringPeking UniversityBeijing100871China Institute of Advanced Materials&Key Lab of Fluorine and Silicon for Energy Materials and chemistry of Ministry of Education College of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang330022China

A series of novel side-chain liquid crystalline(SCLC)copolymers were synthesized by attaching two distinct mesogenic units,namely a chiral cholesteryl-based monomer(M1)and an achiral biphenyl-based monomer(M2),to a poly(3-mercaptopropylmethylsiloxane)(PMMS)backbone via thiol-ene click *** influence of side chain composition on the self-assembly behavior and phase structures of these SCLC copolymers was systematically investigated using different *** indicate that three distinct liquid crystalline phases and four unique molecular configurations were identified within the polymer series,with the emergence of the liquid crystalline phase being a synergistic outcome of the two distinct side *** study underscores the critical influence of side chain dimensions,rigidity,and spatial volume on the self-assembly structures and phase characteristics of liquid crystalline polymers,providing valuable insights for the rational design and development of advanced functional materials with tailored properties.

关键词： Liquid crystalline copolymers Self-assembly Phase structure Chiral molar ratio

Design of artificial biomimetic channels with Na^(+)permeation rate and selectivity potentially outperforming the natural sodium channel

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8638-8646页

作者： zhi Zhu Yan Zhao Chao Chang Shaojian Yan Tingyu Sun Shiyu Gu Yangmei Li Dengsong zhang Chunlei Wang Xiao Cheng Zeng School of Optical-Electrical and Computer engineering University of Shanghai for Science and TechnologyShanghai 200093China Innovation Laboratory of Terahertz Biophysics National Innovation Institute of Defense TechnologyBeijing 100071China School of Physics Peking UniversityBeijing 100871China International Joint Laboratory of Catalytic chemistry College of SciencesShanghai UniversityShanghai 200444China department of Materials science and engineering City University of Hong KongHong Kong 999077China

Artificial ion channels that enable high-efficiency ion transport have important implications in nanofluidics and biomedical applications such as drug ***,we show a simulation-based chemical design of a biomimetic sodium channel that possesses permeation rate and selectivity potentially higher than those of the state-of-the-art natural vertebrate voltage-gated sodium ***,our theoretical findings have undergone empirical testing,aligning well with the Arrhenius law as derived from a diverse range of experimental *** high-efficiency ion transport is achieved by anchoring the carboxylate functional groups within the channel filter.A key chemical guiding principle underlying the ion channel design is that the free-energy barrier for the Na^(+)passage across the channel should be comparable to typical thermal energy at room *** the implementation of the chemical design,we found that the relatively low free-energy barrier can be attributed to the compensation effect of the carboxylate groups to the partially lost oxygen shell of the ion within the ion channel,as well as to the consonant vibration of the ions inside and outside the *** mechanistic understanding brings new insight,at the molecular level,into the high-efficiency ion transport across the designed membrane *** proof of principle achieved from the simulations will stimulate future experimental confirmation and potential applications of the high-performance artificial channels in nanofluidics and in bioinspired iontronics.

关键词： sodium channels anchoring carboxylate functional groups molecular dynamics simulations low free-energy barrier for ion passage thermal kinetic energy

New sustainable polymers with on-demand depolymerization property

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science china chemistry 2024年第9期67卷 2803-2841页

作者： Yangyang Sun Zesheng An Yanshan Gao Rongrong Hu Ye Liu Hua Lu Xiao-Bing Lu Xuan Pang Anjun Qin Yong Shen Youhua Tao Yu-Zhong Wang Junpeng Wang Gang Wu Guang-Peng Wu Tie-Qi Xu Xing-hong zhang Yuetao zhang Zhenbiao zhang Jian-Bo Zhu Miao hong zhibo Li State Key Laboratory of Organometallic chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China State Key Laboratory Base of Eco-Chemical engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao266042China State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Fine Chemicals Frontiers Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China beijing National Laboratory for molecular sciences Center for Soft Matter Science and EngineeringKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Key Laboratory of polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China The Collaborative Innovation Center for Eco-Friendly and Fire-Safety polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)College of ChemistryState Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610064China School of polymer science and polymer engineering the University of AkronAkronOH 44325USA MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China State and Local Joint engineering Laboratory for Novel Functional polymeric Materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationSuzhou Key Laboratory of Macromolecular Design and Precision SynthesisCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

To combat the crisis of today's synthetic polymers arising from unsustainable production and disposal,it is essential for the synthetic polymer community to reshape the current polymer industry with sustainable *** an emerging class of sustainable polymers,the development of chemically depolymerizable polymers(CDPs),which can undergo closed-loop depolymerization/repolymerization cycles to reproduce virgin polymers without the loss of properties from recovered monomers,offers an ideal solution to preserve finite natural resources,provides a feasible solution to the end-of-life issue of polymer waste,and thereby establishes a circular materials ***,two grand key challenges have been encountered in the establishment of practically useful CDPs:how to balance polymerization and depolymerization ability and how to unify conflicted depolymerizability and physical ***,this critical review article presents our vision for summarizing feasible strategies to overcome the above two significant challenges and the design principles for constructing an ideal CDP by highlighting selected major progress made in this rapidly expanding field.

关键词： chemically depolymerizable polymers sustainable polymers depolymerization monomer recovery degradation plastics