02369nas a2200205   4500008004100000245015500041210006900196260000800265300001400273490000800287520159000295100001901885700002001904700002101924700002401945700002001969700001801989700002402007856013202031       2016                        eng d00aEffective noncovalent functionalization of poly(ethylene glycol) to reduced graphene oxidenanosheets through gamma-radiolysis for enhanced lubrication0 aEffective noncovalent functionalization of polyethylene glycol t  cFEB  a2139-21480 v1203 aHigh-quality reduced graphene oxide (rGO) nanosheets (NSs) were synthesized by the oxidation of graphite followed by hydrazine treatment for the reduction of the oxygen functionalities. gamma-Radiolysis was then used for the functionalization of the rGO-NSs with poly(ethylene glycol) 200 (PEG200). The functionalization resulted in the intercalation of PEG200 molecules in rGO through hydrogen bonding between the hydroxyl groups of rGO and the oxygen atoms of PEG200 molecules. This resulted in an increase in the d spacing of the graphene sheets and a decrease in the defect density of the carbon network in the rGO. The friction coefficient and wear of sliding steel surfaces were reduced by 38% and 55%, respectively, when 0.03 mg mL(-1) PEG200-functionalized rGO dispersed in PEG200 was used. The lubrication properties can be described by bipolar interactions between PEG200 and rGO, leading to effective dispersion. Chemical analysis of wear particles showed decomposition of rGO into nanosized graphite domains, as exhibited by mechanical energy produced in tribo-contact. Moreover, these domains formed effective and stable tribofilms on the steel wear tracks that easily sheared under the action of contact stress. This significantly enhanced the antifriction and antiwear properties, resulting in improved oxidation resistance of PEG200 under the tribo-contact. It was found that, at high rGO concentrations, the lubrication efficiency decreased as a result of graphene-graphene intersheet collisions, producing mechanical energy and chemical defects at contact interfaces.1 aGupta, Bhavana1 aKumar, Niranjan1 aPanda, Kalpataru1 aMelvin, Ambrose, A.1 aJoshi, Shailesh1 aDash, Sitaram1 aTyagi, Ashok, Kumar  uhttps://library.ncl.res.in/content/effective-noncovalent-functionalization-polyethylene-glycol-reduced-graphene-oxidenanosheets02170nas a2200205   4500008004100000022001400041245010200055210006900157260006700226300001200293490000600305520141000311100001901721700002001740700002101760700002401781700002001805700001801825856012101843       2016                        eng d  a2196-735000aMolecular-Pillar-supported functionalized reduced graphene-oxide for energy efficient lubrication0 aMolecularPillarsupported functionalized reduced grapheneoxide fo  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUL  a16001610 v33 a<p>Molecular-pillar-supported basal plane of reduced graphene oxide (rGO) is fabricated by polymerizing polyaniline (PANI). In the presence of poly(ethylene glycol) (PEG200), the gamma-radiolysis is used for modifying the functionalization and improving the structural symmetry of PANI and PEG grafted rGO (PANI-PEG-g-rGO). The PANI is covalently and noncovalently grafted onto the surface of the graphene sheets. Carboxyl groups of rGO are linked to the nitrogen atoms in the PANI backbone and an accompanying noncovalent interaction between alkyl chains of grafted PANI and hydrooxylated rGO is formed. Raman and Fourier transform infra-red results confirm existence of stretching vibrations of benzenoid and quinonoid rings in PANI-PEG-g-rGO-functionalized composite, indicating grafting between PANI and rGO through pi-pi interaction. Furthermore, PEG-functionalization through hydrogen bonding with rGO is confirmed when hydroxyl group from the rGO combines with oxygen of PEG. X-ray photoelectron spectroscopy reveals significant increase in carbon, while loading PANI network with rGO followed by gamma-irradiation. Antifriction and antiwear properties of graphene nanocomposite are considerably enhanced to 68.4% and 48%, respectively, as compared to pristine PEG. The unique lubrication properties are explained by PEG functionalized molecular PANI-pillar structure across basal plane of rGO.</p>1 aGupta, Bhavana1 aKumar, Niranjan1 aPanda, Kalpataru1 aMelvin, Ambrose, A.1 aJoshi, Shailesh1 aDash, Sitaram  uhttps://library.ncl.res.in/content/molecular-pillar-supported-functionalized-reduced-graphene-oxide-energy-efficient