02252nas a2200253 4500008004100000022001400041245011800055210006900173260000900242300001200251490000800263520137900271653002701650653002301677653001401700653002401714653002401738100001901762700002101781700002701802700002401829700001401853856013101867 2019 eng d a0013-468600aStudies on nano composites of SPEEK/ethylene glycol/cellulose nanocrystals as promising proton exchange membranes0 aStudies on nano composites of SPEEKethylene glycolcellulose nano cJAN  a260-2720 v2933 a

The present work deals with fabrication and characterisations of nano-composite membranes composed of sulfonated poly (ether ether ketone) (SPEEK) cross-linked and reinforced with ethylene glycol (EG) and cellulose nanocrystals (CNCs) respectively. The thin films of cross-linked composite membranes were prepared by solvent casting method and further analysed for physicochemical and electrochemical properties to execute their applicability as promising proton exchange membrane (PEM) in fuel cells. The process of cross-linking helps to improve the strength and dimensional stability of bare SPEEK membranes without compromising with conductivity. However, presence of CNCs further improves the strength and provides an effective pathway for the conduction of protons in membranes by interacting through their surface hydroxyl and sulfonic acid groups with ionic moieties of polymer matrix. All prepared composite membranes showed good oxidative and thermal stability along with good proton conductivity. The cross-linked SPEEK membranes with 4 wt% loading of CNCs possess an appreciable proton conductivity of 0.186 S/cm at 95 degrees C and 95% RH which is comparable to Nafion 117. From the view point of above studies, the prepared nano-composite can be described as promising proton exchange membrane for fuel cells. (c) 2018 Elsevier Ltd. All rights reserved.

10aCellulose nanocrystals10aCross-linked SPEEK10afuel cell10aoxidative stability10aproton conductivity1 aBano, Saleheen1 aNegi, Yuvraj, S.1 aIllathvalappil, Rajith1 aKurungot, Sreekumar1 aRamya, K. uhttp://library.ncl.res.in/content/studies-nano-composites-speekethylene-glycolcellulose-nanocrystals-promising-proton-exchange01910nas a2200301 4500008004100000022001400041245007100055210006900126260000900195490000700204520095100211653002301162653001801185653002401203653003801227653002601265653002401291100002801315700001601343700002401359700002601383700001601409700001901425700001601444700002401460700001901484856010501503 2023 eng d a1433-785100aChemically gradient hydrogen-bonded organic framework crystal film0 aChemically gradient hydrogenbonded organic framework crystal fil cJUL 0 v623 a

Hydrogen-bonded organic frameworks (HOFs) are ordered supramolecular solid structures, however, nothing much explored as centimetre-scale self-standing films. The fabrication of such crystals comprising self-supported films is challenging due to the limited flexibility and interaction of the crystals, and therefore studies on two-dimensional macrostructures of HOFs are limited to external supports. Herein, we introduce a novel chemical gradient strategy to fabricate a crystal-deposited HOF film on an in situ-formed covalent organic polymer film (Tam-Bdca-CGHOF). The fabricated film showed versatility in chemical bonding along its thickness from covalent to hydrogen-bonded network. The kinetic-controlled Tam-Bdca-CGHOF showed enhanced proton conductivity (8.3x10(-5) S cm(-1)) compared to its rapid kinetic analogue, Tam-Bdca-COP (2.1x10(-5) S cm(-1)), which signifies the advantage of bonding-engineering in the same system.

10aChemical Gradience10aCrystal Films10aFree-Standing Films10ahydrogen-bonded organic framework10aInterfacial Chemistry10aproton conductivity1 aMohammed, Abdul, Khayum1 aRaya, Jesus1 aPandikassala, Ajmal1 aAddicoat, Matthew, A.1 aGaber, Safa1 aAslam, Mohamed1 aAli, Liaqat1 aKurungot, Sreekumar1 aShetty, Dinesh uhttp://library.ncl.res.in/content/chemically-gradient-hydrogen-bonded-organic-framework-crystal-film02306nas a2200265 4500008004100000022001400041245015400055210006900209260000800278300001100286490000700297520133900304653002301643653003301666653002201699653003801721653002401759100001801783700001501801700002401816700002401840700002601864700002001890856013001910 2023 eng d a2352-940700aUnlocking the potential of proton conductivity in guanidinium-based ionic covalent organic nanosheets (iCONs) through pore interior functionalization0 aUnlocking the potential of proton conductivity in guanidiniumbas cAUG a1018660 v333 a

Recently, scientists have been exploring the incorporation of proton carriers such as water and phosphoric acid (PA) into the pores and channels of porous materials to enhance proton conduction performance. Ionic covalent organic nanosheets (iCONs) have been identified as promising functional materials due to their inbuilt ionic interfaces, which can facilitate strong interaction with counter ions present inside the pore structure and thus shorten ion transport pathways. However, there is a lack of research related to proton conductivity in iCONs loaded with PA. To address this, we prepared three functionalized guanidinium-based iCONs using a solvothermal condensation reaction between guanidinium amine (TG) and functionalized terephthaldehyde (Da, Dha, and Dma). PA was also incorporated into the iCON structure via ex situ loading to observe its effects on proton conduction performance. The results showed that both the iCONs and PA-iCONs were highly stable in water, organic solvents, acidic and basic media. Amongst these PA-iCONs, one with hydroxyl-functionalization (PA-DhaTG) displayed high proton conductivity at 90 degrees C and 95% relative humidity due to a Grotthuss mechanism for protons. These functionalized guanidinium-based iCONs could prove useful for applications in energy conversion devices.

10achemical stability10aFunctionalized pore interior10aGuanidinium group10aionic covalent organic nanosheets10aproton conductivity1 aKumar, Sushil1 aHu, Jiahui1 aPandikassala, Ajmal1 aKurungot, Sreekumar1 aAddicoat, Matthew, A.1 aSzekely, Gyorgy uhttp://library.ncl.res.in/content/unlocking-potential-proton-conductivity-guanidinium-based-ionic-covalent-organic-nanosheets