Middle Est Journl of Applied Sciences Volume : 5 Issue : 4 Oct.-Dec. 215 Pges: 94-944 Preprtion nd Dielectric Properties of Mgnetite/Chitosn Nnocomposite Film 1 Mgd D. Bdry, 2 Mohmmed A. Wh, 1 R K. Khled, 3 Ahmed A. Frghli 1 Deprtment of Physicl Chemistry nd 2 Deprtment of Inorgnic Chemistry, Ntionl Reserch Centre, El- Behoos St., Dokki, Giz, Egypt. 3 Deprtment of Chemistry, Fculty of Science, Beni-Suef University, Egypt. ABSTRACT Pure mgnetite (Fe 3O 4) nnoprticles were synthesized nd successfully coted with chitosn (CS). XRD ptterns confirmed the formtion of pure spinel Fe 3O 4 structure without presence of ny other phses. TEM results reveled tht the Fe 3O 4 nnoprticles were 17.6-19.5 nm in size with good homogenously dispersion. The frequency dependences of the dielectric constnt s well s the dielectric loss hve een reported t different tempertures for pure CS nd Fe 3O 4/CS nnocomposite films. Dielectric mesurements showed tht oth of them recorded lower vlues with incresing frequency, wheres they showed proportionl reltionship with temperture. Key words: Mgnetite, Chitosn, Electricl Properties Introduction Among ll iron oxide nnoprticles, mgnetite (Fe 3O 4) represents the most interesting properties due to its unique structure i.e. the presence of iron ctions in two vlence sttes, Fe 2+ nd Fe 3+ on tetrhedrl nd octhedrl sites with n inverse cuic spinel structure (Rhmn et l., 212). The electrons cn hop etween Fe 2+ nd Fe 3+ ions in the octhedrl sites t room temperture, rendering mgnetite n importnt clss of hlf-metllic mterils (Ozky et l., 29). However, ggregtion of Fe 3O 4 nnoprticles due to high surfce re nd mgnetic dipole interction etween nnoprticles hs limited their pplictions. This prolem cn perhps e overcome y dispersing Fe 3O 4 nnoprticles in iopolymer mtrix (Kushik et l., 28, Kushik et l., 29). Among these iopolymers, Chitosn (CS) is polyminoscchride produced y decetyltion of chitin nturlly extrcted from shells of crs nd shrimps, or isolted from the cell wlls of fungi. It displys n excellent film-forming ility, good dhesion, iocomptiility, high mechnicl strength nd susceptiility to chemicl modifiction due to the presence of rective hydroxyl nd mino functionl groups (Kushik et l., 29). These composites re technologiclly importnt nd hve een used in mny pplictions including mgnetic recording medi nd mgnetic fluids for the storge nd retrievl of informtion, mgnetic resonnce imge enhncement, nd others (Guin et l., 29; Misr et l., 24; Misu et l., 211 nd Yelenich et l., 213). In this study, pure Fe 3O 4 nnoprticles were prepred y hydrotherml method nd successfully coted with CS iopolymer to form Fe 3O 4/CS nnocomposite film. Structurl nd morphologicl chrcteristics of the prepred nnoprticles were reveled. The dielectric mesurements for pure CS nd Fe 3O 4/CS nnocomposite films were studied s function of frequency t different tempertures. Experimentl: Preprtion of Fe3O4 nnoprticles, CS film nd Fe3O4/CS nnocomposite film: Fe 3O 4 nnoprticles ws prepred y dissolving 2.5g of ferrous sulphte hepthydrte (SHAM LAB, Syri) in 3ml distilled wter, then 1ml of PEG-2 (Englnd) ws dded to the solution t 3 C under vigorous stirring. During the rection process, NH 4OH (ABCO CHEMIE, Englnd) ws dded up to ph vlue of 1. Then,.27ml of H 2O 2 (LOBA CHEMIE, Indi) solution ws dded to the stirred mixture nd stirred for 2 min. The mixture ws trnsferred into the utoclve nd heted t 16 C in the oven for 15 h. The smple ws wshed y ethnol nd distilled wter severl times. Finlly, the smple ws dried t 7 C (Li et l., 28). Fe 3O 4/CS nnocomposite film ws synthesized y dissolving 1g of chitosn (MALLINCKRODT, Frnce) in 1% CH 3COOH solution, then dding.5g of the prepred Fe 3O 4 nnoprticles. The solution ws ultrsonicted for Corresponding Author: Mgd D. Bdry, 1Deprtment of Physicl Chemistry, Ntionl Reserch Centre, El-Behoos St., Dokki, Giz, Egypt E-mil: m_dwy9@yhoo.com 94
2 h. Finlly, the mixture ws poured into petridishes. Pure CS film ws synthesized without ddition of the prepred Fe 3O 4 of nnoprticles. The prepred compounds were chrcterized y X-ry powder diffctometer (X pert pro. PANlyticl, Hollnd), trnsmission electron microscopy (HR TEM-JEM 21, JEOL, Jpn). Dielectric mesurements of the prepred smples hd een mesured over the temperture rnge (25-8 C) nd frequency rnge (1 HZ-5 MHZ) using HIOKI Jpn 3532-5 LCR HI TESTER tht hs een interfced to computer. Results nd Discussion XRD results: The crystl structures of pure CS, Fe 3O 4 nnoprticles nd Fe 3O 4/CS nnocomposite film reveled y XRD re presented in (Fig. 1-c). XRD ptterns of pure CS showed distinct crystlline peks t round 2θ vlues 2, 26.7 nd 28.3, nd this is ecuse of presence of plenty of OH nd NH2 groups in the chitosn structure, which could form stronger inter nd intrmoleculr hydrogen onds (Rmy et l., 212). XRD ptterns of Fe 3O 4 nnoprticles exhiited typicl Fe 3O 4 cuic spinel structure (Cuong et l., 212). The positions nd reltive intensities of ll diffrction peks mtch well with those from the JCPDS crd numer 89-4319 for Fe 3O 4. XRD ptterns of Fe 3O 4/CS nnocomposite film showed intensity decresing of the diffrction lines of the composite indicting tht the Fe 3O 4 prticles were successfully coted y morphous CS (Slh El- Din et l., 211). It is lso evident tht the CS coting process did not result in phse chnge of Fe 3O 4 MNP (Chen et l., 211). The verge crystl size of pure Fe 3O 4 nd Fe 3O 4/CS nnocomposite ws 19.2 nd 22.9nm, respectively. Fig 1: XRD ptterns of () pure CS nd () Fe 3O 4 nnoprticles nd (c) Fe 3O 4/CS nnocomposite film TEM nlysis: TEM imge of pure Fe 3O 4 reveled tht the smple consists of uniform sphericl prticles with nrrow size distriution nd verge prticle size of 19.5 nm. This is consistent with XRD dt clculted y the Scherrer s formul. Wheres TEM imge of Fe 3O 4/CS nnocomposite film, reveled uniformly dispersion of Fe 3O 4 nnoprticles with 3.4 nm verge prticle size emedded inside CS mtrix. 941
Fig. 2: TEM imges of () Fe 3O 4 nnoprticles nd () Fe 3O 4/CS nnocomposite film. Electricl properties: The frequency dependence of dielectric constnt t different tempertures for pure CS nd Fe 3O 4/CS nnocomposite films in the frequency rnge 1Hz-5MHz ws shown in Fig. 3 nd. It could e noticed tht the dielectric constnt for the smples presented reltively high vlue t low frequency rnge, decresed with incresing frequency nd lmost remined independent of pplied externl field t high-frequency division. It cn e relized tht; t lower frequency, the dipoles in the system cn reorient themselves to respond to pplied electric field. Wheres t higher frequency, the decrese of dielectric constnt vlues ws ttriuted to the lg of molecules towrds the pplied electric field nd this could e explined y the difficulty of dipoles orienttion in this frequency rnge (Srivstv et l., 214). Moreover, it ws lso oserved tht the dielectric constnt (ε ) of Fe 3O 4/CS nnocomposite film ws gretly influenced nd ws found to e higher thn tht of pure CS film. On the other hnd, the dielectric constnt incresed with incresing temperture nd this increse my e due to the therml energy supplied to the mteril which is sufficient enough to free the loclized dipoles nd they lign themselves in the direction of pplied field (Joshi et l., 214). Dielectric constnt 12 25 C 4 C 1 6 C 7 C 8 6 4 2 Dielectric constnt 85 8 75 7 65 6 55 5 45 4 35 3 25 2 15 1 5-5 25 C 4 C 6 C 7 C Fig. 3: Vrition of dielectric constnt with frequency t different tempertures for () pure CS film nd () Fe 3O 4/CS nnocomposite film. Fig. 4 nd demonstrted the dielectric loss of pure CS nd Fe 3O 4/CS nnocomposite films, respectively s function of frequency t different tempertures. It ws oserved tht the dielectric loss (ε ) of the smples decresed s the frequency incresed nd lmost remined constnt t higher frequency. The trend oserved could e scried to dipole polriztion. Moreover, it ws lso oserved tht the dielectric loss of Fe 3O 4/CS nnocomposite film ws gretly influenced nd ws found to e higher thn tht of pure CS film. On the other hnd, the increse in dielectric loss with incresing temperture my e ttriuted to incresing lttice virtions nd cretion of some phonons which interct with the chrge crriers giving rise to electron phonon scttering (Joshi et l., 214). 942
Dielectric loss 25 2 15 1 5 25 C 4 C 6 C 7 C Dielectric loss 18 25 C 4 C 16 6 C 14 7 C 12 1 8 6 4 2 Fig. 4: Vrition of dielectric loss with frequency t different tempertures for () pure CS film nd () Fe 3O 4/CS nnocomposite film. Conclusion Pure Fe 3O 4 nnoprticles were prepred y hydrotherml method nd successfully coted with CS iopolymer. XRD ptterns nd TEM microgrphs confirmed formtion of pure sphericl Fe 3O 4 nd men dimeter of 19.5. The dielectric constnt nd dielectric loss vlues decresed with incresing frequency nd incresed with temperture increse. Acknowledgements Authors re thnkful to Prof. Dr. Mhmoud Frg Zwrh, Professor of Chemistry of Advnced Mterils nd Nnotechnology (Ntionl Reserch Center), who llowed for doing this work t his l. References Chen, J.P., P. C. Yng, Y. H. M, T.Wu, 211. Chrcteriztion of chitosn mgnetic nnoprticles for in situ delivery of tissue plsminogen ctivtor, Crohydrte Polymers., 84 : 364-372. Cuong, N.D., T.T.Ho, D.Q.Khieu, T.D.Lm, N.D.Ho, N.V.Hieu, 212. Synthesis, chrcteriztion, nd comprtive gs-sensing properties of Fe 2O 3 prepred from Fe 3O 4 nd Fe 3O 4-chitosn, Journl of Alloys nd Compounds., 523 :12 126. Guin, S.P., 29. Mgnetic Nnoprticles., Wiley-VCH, Weinheim. Joshi, S., M. Kumr, S. Chhoker, G. Srivstv, M. Jewriy, V.N.Singh, 214. Structurl, mgnetic, dielectric nd opticl properties of nickel ferrite nnoprticles synthesized y co-precipittion method, Journl of Moleculr Structure., 176 : 55-62. Kushik, A., R. Khn, P. R. Solnki, P. Pndey, J. Alm, S. Ahmd, B. D. Mlhotr, 28. Iron oxide nnoprticles chitosn composite sed glucose iosensor, Biosens Bioelectron., 24 : 676 683. Kushik, A., P. R.Solnki, A. A. Ansri, B. D. Mlhotr, S. Ahmd, 29. Iron oxide-chitosn hyrid nnoiocomposite sed nucleic cid sensor for pyrethroid detection, Biochemicl Engineering Journl., 46 : 132-14. Kushik, A., P. R. Solnki, A. A. Ansri, G. Sumn, S. Ahmd, B. D. Mlhotr, 29. Iron oxide-chitosn nnoiocomposite for ure sensor, Sensors nd Actutors B: Chemicl., 138 : 572-58. Li, G.Y., Jing Y.R., K. L. Hung, P. Ding, J. Chen, 28. Preprtion nd properties of mgnetic Fe3O4 chitosn nnoprticles, Journl of Alloys nd Compounds., 466 : 451-456. Misr, R. D. K., S. Gul, A. Kle, W.F. Egelhoff Jr, 24. A comprison of the mgnetic chrcteristics of nnocrystlline nickel, zinc, nd mngnese ferrites synthesized y reverse micelle technique, Mter. Sci. Eng., B 111 : 164-174. Misu, T., N. Skmoto, K. Shinozki, N. Adchi, H. Suzuki, N. Wkiy, 211. Mgnetic nd opticl properties of MgAl 2O 4e (Ni.5Zn.5)Fe 2O 4 thin films prepred y pulsed lser deposition, Sci. Technol. Adv. Mter. 12 : 3448. 943
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