LIQUID CRYSTALS
·
2022
·
IF 2.676
Xiang-Yu Ma,Qiu-Cheng Li,Cheng-Han Song,Hong-Shuang Zhang,Yuan-Sen Zhi,Xiao-Zhi He
Fluorescent liquid crystal polymers have attracted much attention because of the combination of fluorescence, liquid crystallinity and processability. In this study, we designed and synthesised two series of photoluminescent cholesteric liquid crystal polysiloxanes, which contained cholesterol mesogens and fluorescein methyl ester with different side chain lengths. The chemical structures and liquid crystal properties of the polymers were investigated by the usual methods. The photoluminescent property were characterised by fluorescence spectroscopy. At the same time, the effects of the lengths of the fluorescent group chains on the liquid crystal and fluorescence properties of the polymers were studied. The results showed that the synthesised polymers possessing very good fluorescent and liquid crystal properties, which may has certain practical value and application prospect.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2020
·
IF 4.613
Shang Gao,Ze-ping Liu,Yue-hua Cong,Xiao-zhi He,Bao-yan Zhang,Fan-bao Meng,Ying-gang Jia
With polymethylhydrogensiloxane (PMHS) as the main chain, two series side-chain cholesteric liquid crystal polymers (ChLCPs) with different liquid crystal side chain lengths were prepared by hydrosilylation reaction. Then two series of cholesteric fluorescent liquid crystal polymers (FL-ChLCPs) were obtained by etherification reaction. The obtained FL-ChLCPs have both excellent mesomorphic behavior, and great photoluminescent property. We confirmed their chemical structures by FT-IR, and 1 H NMR spectroscopy , and found them with excellent thermal stability by TGA . We characterized their mesomorphic behavior and thermal performance by POM, DSC and XRD , and confirmed all the polymers belonged to cholesteric phase. FL-ChLCPs emitted different-intensity fluorescence under UV light, and we found some regularity by PL spectrum.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Tao Ban,Maolian Guo,Yajie Wang,Yiyang Zhang,Xiuling Zhu
Fabrication of aromatic proton exchange membrane (PEM) with excellent conductivity and stability is a long-standing challenge. Here, we propose an aromatic PEM containing multiple sulfonated alkyl side chains (SAFPAEK-x and SAFPAEF-x), and then implement an ideal strategy to address the trade-off between conductivity and stability by optimizing the side chain length and main chain polarity. Specifically, the synthesized PEMs achieve an efficient proton transport (proton conductivity >0.124 S cm −1 at 80 °C) under the synergistic effect of multiple pendant sulfonate groups and a pronounced microphase separation structure. Meanwhile, regulating the polarity of the hydrophobic domain via introducing fluorinated structures can effectively suppress the swelling behavior, so that SAFPAEF-x display excellent dimensional stability (swelling ratio <10% at 80 °C). The theoretical calculations of molecular models and ex-situ experiments demonstrate that appropriate increases in side chain length and main chain polarity lead to noticeably improved radical stability of aromatic PEMs. Finally, the laboratory-assembled direct borohydride fuel cell using our rationally designed PEMs reaches the highest peak power density of 191.17 mW m −2 at room temperature, outperforming the Nafion 115 (95.87 mW m −2 ) under the same conditions. Therefore, this membrane design strategy stimulates great potential in designing high-performance aromatic PEMs for fuel cells.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Huichao Zhu,Jianjun Yang,Mingyuan Wu,Qingyun Wu,Jiuyi Liu,Jianan Zhang
A series of tartaric acid (TA) esters with different side chain lengths [dibutyl TA esters (DBTAE)-Cn], as plasticizers for poly(vinyl chloride) (PVC), is herein reported. Their structures have been fully characterized using proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Their compatibility and plasticizing effect for soft PVC were evaluated using thermogravimetric analysis, dynamic mechanical analysis, tensile testing, and migration testing. The results showed that all these TA esters exhibit good plasticizing performance. At a concentration of 30 phr in PVC, the best results for the plasticizing effect, in terms of glass transition temperature reduction and elongation at break, were achieved when the ester DBTAE-C4 was used. However, the longer side chains of these esters improved the thermal stability of soft PVC blends yet exacerbated the migration behavior of these esters from PVC films in n-hexane. The properties of the plasticized PVC blends depended on the structural features of DBTAE-Cn. The plasticizing performances of the esters DBTAE-C1 and DBTAE-C4 rivaled that of dioctyl phthalate (DOP), suggesting that they have the potential to replace DOP in soft PVC materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Yiming Xiao,Shihao Wang,Guiying Tian,Jun Xiang,Lei Zhang,Penggao Cheng,Jianping Zhang,Na Tang
Phosphoric acid-doped polybenzimidazole membranes have exhibited great potential in high-temperature proton exchange membrane applications, but proton conductivity and stability should be further improved for high performance fuel cells . Herein, a series of grafted polybenzimidazoles containing benzimidazole type side pendant were successfully prepared by facile N-substitution reaction without any catalyst. These grafted polybenzimidazole membranes with side chains of benzimidazole group exhibit excellent properties in the doping level of phosphoric acid, retention stability of phosphoric acid and proton conductivity under certain mechanical properties , oxidation resistance and thermal stability. Importantly, the phosphoric acid (PA) retention stability and proton conductivity can be preciously controlled by adjusting the length of side chain and the number of benzimidazole groups. With the acid doping level of 19.3, the grafted membrane exhibits a high conductivity of 101 mS cm −1 and a great power density of 305 mW cm −2 at 160 °C without humidification. The molecular dynamics simulation show that the improved performance of the grafted membrane is mainly due to the increase in the free volume of the polymer membrane, the enhancement of the binding energy and the densification of the hydrogen bond network structure between the polymer membrane and phosphoric acid.
研究领域:
材料科学
·
燃料电池研究
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 23
·3287
·
IF 4.7
Han Zhou,Zaitian Cheng,Guoxing Pan,Lin Hu,Fapei Zhang
The performance of organic field-effect transistors (OFETs) is highly dependent on the dielectric–semiconductor interface, especially in ion-gel-gated OFETs, where a significantly high carrier density is induced at the interface at a low gate voltage. This study investigates how altering the alkyl side chain length of donor–acceptor (D-A) copolymers impacts the electrical performance of ion-gel-gated OFETs. Two difluorobenzothiadiazole-based D-A copolymers, PffBT4T-2OD and PffBT4T-2DT, are compared, where the latter features longer alkyl side chains. Although PffBT4T-2DT shows a 2.4-fold enhancement of charge mobility in the SiO2-gated OFETs compared to its counterpart due to higher crystallinity in the film, PffBT4T-2OD outperforms PffBT4T-2DT in the ion-gel-gated OFETs, manifested by an extraordinarily high mobility of 17.7 cm2/V s. The smoother surface morphology, as well as stronger interfacial interaction between the ion-gel dielectric and PffBT4T-2OD, enhances interfacial charge accumulation, which leads to higher mobility. Furthermore, PffBT4T-2OD is blended with a polymeric elastomer SEBS to achieve ion-gel-gated flexible OFETs. The blend devices exhibit high mobility of 8.6 cm2/V s and high stretchability, retaining 45% of initial mobility under 100% tensile strain. This study demonstrates the importance of optimizing the chain structure of polymer semiconductors and the semiconductor–dielectric interface to develop low-voltage and high-performance flexible OFETs for wearable electronics applications.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Xi Bin Yue,Ying Jie Liu,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Anion exchange membranes (AEMs) are one of the most critical materials determining the fuel cell (FC) performance. From current reports, there are still many limit factors for AEMs, such as conductivity, mechanical performance, power density and durability, which greatly affect their practicality. Here, we introduce a range of arylfluoroketone monomers with different side chain lengths into the poly (aryl-alkylene) matrix material using a copolymerization strategy to get AEMs. This study aims to investigate the effect of side chain length on the performance of AEMs, such as phase separation, ion conductivity and mechanical properties. Due to the existence of long alkyl side chains , QTPNPC4 shows significant hydrophilic aggregation, outstanding OH − conductivity (158.6 mS cm −1 , 80 °C) and excellent flexibility (109.1 %). Meanwhile, QTPNPC4 exhibits remarkable ex-situ durability (96.3 %) and chemical stability (96.6 %) after soaking in a 2 M NaOH solution for 1560 h at 80 °C. In addition, the peak power density (PPD) of a single cell with QTPNPC4 reaches 927 mW cm −2 (80 °C), and the membrane has good in-situ durability (0.689 mV h −1 ).
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2025
·
IF 12.5
Huijing Chen,Juxin He,Wanchun Li,Zhirong Wang,Muying Du,Jianquan Kan
Esterified starch exhibits desirable freeze-thaw stability and emulsifying properties; however, there are limited reports on how the side-chain length of the acid anhydride affects the antifreeze activity and microencapsulation ability of starch. In this study, four types esterified starch with different hydrophobic chains were prepared and their physicochemical characteristics were explored. The results indicated that acid anhydride modification decreased the amylose content and relative crystallinity of native starch and altered its surface composition. Dodecenyl and hexadecenyl succinic anhydrides rendered the starch with relatively low degree of substitution but strong surface hydrophobicity (>120°). The order of anhydrides with different chain lengths to impart emulsifying ability to starch was dodecenyl succinic anhydride > octenyl succinic anhydride > hexadecenyl succinic anhydride > maleic anhydride, whereas the O/W Pickering emulsion storage stability of hexadecenyl succinic anhydride-esterified starch significantly decreased. Moreover, modified starches with superior freeze–thaw stability for microencapsulation improved the freeze-drying resistance of urate-lowering probiotics. Meanwhile, the encapsulated probiotics which passage through a simulated digestion exhibited superior xanthine oxidase inhibition. These results indicate that the appropriate chain-length acid-anhydride-modified starch is a promising cryoprotectant for frozen products.
研究领域:
食品科学
·
生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL RESEARCH
·
2018
·
IF 0.668
Qian Zhao,Yanhua Yang,Kecheng Shen,Xian Tao,Yingzhong Shen
Three novel types of naphthopyran derivatives containing alkoxyl and phenyl moieties, 13-butyl −6,11-dimethyl-3,3-diphenyl-3,13-dihydrobenzo[h]indeno[2,1-f]chromen-13-ol (NP), 13-butyl-3,3-bis(6-methoxy-[1,1′-biphenyl]-3-yl)-6,6-dimethyl-3,13-dihydrobenzo[h] indeno[2,1-f]chromen-13-ol (NP1) and 13-butyl-3,3-bis(6-methoxy-4′-naphthalenyl-[1,1′-biphenyl]-3-yl)-6,11-dimenthyl-3,13-dihydrobenz[h]indeno[2,1-f]chromen-13-ol (NP2), were synthesised and characterised. Measurements indicated that they possessed an excellent photochromic response, a rapid thermal bleaching rate and good fatigue resistance. Meanwhile, the UV maximum absorption wavelengths of NP1 (562 nm) and NP2 (597 nm) appeared bathochromically shifted compared with NP (536 nm). The bleaching rate of NP1 was found to be approximately twice that of NP. The results indicated that the UV maximum absorption wavelength and bleaching rate increase with increasing length of the phenyl side chain moieties. In PMMA film, the compounds showed almost the same photochromic properties in the solid state as in dichloromethane solution. The UV absorbance with high-contrast switching in solid film could be beneficial for practical applications.
研究领域:
有机化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Shilong Wu,Huanhuan Yang,Quan Chen
In this study, we investigated the effect(s) of side-chain length distribution on the transient elongational hardening behavior of polymer melts. For either entangled or unentangled systems, we successfully prepared a series of samples, poly(butyl methacrylate), poly(methyl methacrylate-co-hexyl methacrylate), and poly(methyl methacrylate-co-lauryl methacrylate), abbreviated as PBMA, P(MMA-co-HMA), and P(MMA-co-LMA), respectively, that have the same average length of side chains and similar weight-average molecular weight. These samples exhibited quite different nonlinear elongational behavior despite a similarity of their linear viscoelastic behavior. The transient strain hardening is enhanced on an increase of the side-chain length distribution, namely, in the order of PBMA < P(MMA-co-HMA) < P(MMA-co-LMA), consistently for either the unentangled or entangled series. Given this consistency, the detailed hardening behavior is different, where the unentangled samples exhibit thickening at the Rouse Weissenberg number WiR > 0.1 and thinning at the higher WiR > 1, which can be explained by a combination of the finite extensional nonlinear elasticity and the frictional reduction when chains are highly stretched and coaligned. The degree of friction reduction relies on the length distribution according to the interpenetration of side chains. In comparison, the entangled samples exhibit consistent thinning even when WiR is lower than one, which is attributable to the concurrence of the flow-induced disentanglement.
研究领域:
高分子物理
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 3.7
Zhiping Zhao,Chunfeng Zhang,Xiaojun Zhang,Qiong Tang,Lei Liu,Jinxiang Dong
Nano-silica grease (NSG), an innovative lubricant, is commonly synthesized using base oil thickened with SiO 2 , the choice of appropriate base oil is crucial for obtaining superior performance NSG. Herein, a series of alkylnaphthalene (AN) base oils with different side-chain lengths were synthesized through the alkylation reaction between naphthalene and α-olefin. We first reported the synthesis of NSGs based on the AN base oils, and investigated the influence of the synthetic AN base oils on the rheological behaviors and tribological characteristics of the resulted NSGs. The results indicated that the structural strength of the grease increased as the alkyl chain length rose because it reinforced the contact between the alkylnaphthalene base oil and nano-silica thickener. Meanwhile, tribological tests were conducted to examine the effect of various AN base oils on the lubricating performance of the formed NSGs. The tested results showed that increasing the side chain length of the AN could elevate the friction-reducing and anti-wear properties of the NSG.
研究领域:
材料科学
·
化学工程
·
摩擦学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2013
·Vol. 49
·期 6
·1731-1741
·
IF 2.562
Wenwen Yu,Dezhi Zhang,Miao Du,Qiang Zheng
A series of novel polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites with graded length side chains were prepared from toluene diisocyanate (TDI), polytetrahydrofuran glycol (PTMG), EP, trimethylolpropane (TMP), and diol chain extenders. The effects of the side chain lengths, content, and groups on the damping properties and mechanical properties were investigated. Two damping peaks were observed in the PU/EP IPN system, indicating that the peak damping factor (tan δ ) increased with increased side chain length at low temperatures. The introduction of an apolar side chain slightly narrowed the damping range. However, the side chain carrying polar groups broadened the damping temperature range. The strong H-bond interaction between the ester group of side chain and the N H of hard segments in PU was believed to favor microphase separation to form a larger-sized domain and induce the appearance of the relaxation peak at high temperatures. Consequently, the effective damping temperature range was broadened. The side chain content tethered in the hard segment remarkably influenced the damping properties of PU/EP IPNs both at low and high temperatures. The width and intensity of the tan δ peaks of PU/EP IPNs increased with increased side chain content. The mechanical properties (tensile strength and elongation at break) were significantly affected by the side chain content. Thus, an important method of improving the mechanical damping of elastomers by controlling the side chain molecular structure was established.
研究领域:
高分子材料科学
·
功能高分子
·
阻尼材料
·
复合材料
·
聚合物共混物
·
材料力学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）