Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17Theme F686 - N1123Comparative Study of Humidity Sensing Properties of PVC-Bt6-Cu and PVC-Bt6-Hg ComplexFilmsMavişe ŞEKER 1 , Salih OKUR 1 , Nesli T. YAĞMURCUKARDEŞ 1 , Gülşah KURT 2 , Bedrettin MERCİMEK 3 , Mahmut KUŞ 41Izmir Institute of Technology, Department of Physics Urla/Izmir/TURKEY2Aksaray University, Department of Chemistry, Aksaray/TURKEY3 Selçuk University, Department of Chemistry Education, Selçuklu/Konya/TURKEY4Selçuk University, Department of Chemical Engineering, Selçuklu/Konya/TURKEYAbstract: This study focuses on respectively the characterization of PVC-BT6-Cu complex and PVC-BT6-Hg complex films coated on aquartz surface by drop-casting method for humidity detection and comparison of these two thin films properties. The Resistance and quartzcrystal microbalance (QCM) were employed for the characterization. The change of resistance and resonance frequency was monitored withdifferent increasing and decreasing relative humidity (RH) values between 11% and 97%.The humidity adsorption and desorption kineticsof the PVC-Bt6-Cu complex and PVC-Bt6-Hg complex films was examined by QCM technique.Poly(vinyl chloride) (PVC) was modified withbenzoilizotiyosiyanat and amine derivative and PVCconnected benzoylthiourea ligand (PVC-Bt6) wasobtained.Then Cu and Hg complexes of this ligand weresynthesized.[1] In Fig.1 molecular structure of (a) PVC-Bt6-Cu complex and (b) PVC-Bt6-Hg complex are shown.CH 2 -CHCH 2 -CHCH 2 -CHCH 2 -CH2020%11%11 RH%11%11 RH00%22%22-20%43%43-20-40 %53%53-60%75Cu-PVCCu-PVC-40%75(under %84 RH)%84%84-80%94-60%94-100Hg-PVC (a) -80Hg-PVC (b)%97(under %84 RH)-120200 400 600 800 1000 1200Time/sec0 1000 2000 3000 4000 5000 6000Time/sec0dF/Hz1000dF/HzNNNNy = 4.1948 * e^(0.032107x) R= 0.98952100HNNSOCuSONHNHNNSOHgSONHN- f(Hz)Hgdownward10CuHgupwardCu(c)120 30 40 50 60 70 80 90 100Relative Humidity (%)(a)Figure 1. (a) Chemical structure of synthesized (a)PVC-Bt6- Cucomplex (b)PVC-Bt6- Hg complexQCM is a sensor that extremely sensitive to mass changesin the nanogram scale by measuring the change ofpositions of its resonance frequency and it responds to agiven increase of mass simultaneously, regardless of thespecies deposited.[2-3] We used in our study QCM withthe model of CHI400A Series from CH Instruments(Austin, USA) to monitor the change in the resonancefrequency of quartz crystals between gold electrodesowing to the fact that saturated aquatic solutions which itwas subjected. Relative humidity (RH) values of solutionswere 11%, 22%, 43%, 53%, 75%, 84%, 94% and 97%.1mg/1ml Cu complex and Hg complex were dissolved intetrahidrofuran (THF) solvent and 5μl of solutions werecoated onto QCM thermally evaporated gold electrodeswhich has 17μm separation and 120 nm thickness by dropcastingmethod. QCM frequency shifts and Resistanceversus Time values were observed depending on relativehumidity with Keitley 2420 Sourcemeter and commercialhumidity-temperature sensor.(b)Figure 2. (a) Comparison of QCM frequency shifts of PVC-Bt6-Cu complex and PVC-Bt6-Hg complex for different increasingand decreasing RH values.(b) QCM frequency shifts (Hz) as afunction of time (s) for relative humidity values 11% and %84.(c) The frequency response of PVC-Bt6-Cu and PVC-Bt6-Hgfilms covered QCM adsorption-desorption process at fixed pointrelative humidity conditions between 11% and 97% RH.In Fig.2(a) QCM frequency responses of PVC-Bt6-Cuand PVC-Bt6-Hg comlexes are occured step by stepdepending on the different relative humidity conditionsbetween 11% and %97. In Fig.2(b) We can see QCMfrequency shifts (Hz) as a function of time (s) for relativehumidity values of 11% and %84. The adsorption anddesorption data taken from Fig.2(a) shows an exponentialdependence on relative humidity RH as shown in Fig.2(c).Fig.2 shows the frequency response of PVC-Bt6-Hgcomplex based sensor is more sensitive than PVC-Bt6-Cucomplex based sensor for humidity changes at roomtemperature.*Corresponding author: salihokur@iyte.edu.tr[1] R. Navarro, K. Bierbrauer, C. Mijangos, E. Goiti, H.Reinecke, Polym. Degrad. Stab. 93, 585–591 (2008)[2] P. Payra, P.K. Dutta, Zeolites: a premier, in: S.M. Auerbach,K.A. Carrado, P.K. Dutta (Eds.), Handbook of Zeolite Scienceand Technology, Marcel Dekker Inc., New York, 2003.[3] S. Okur, M. Kus, F. Özel, V. Aybek, M. Yilmaz, Talanta,81;1-2; 2010; 248.6th Nanoscience and Nanotechnology Conference, zmir, 2010 693