Third Day Poster Session, 17 June 2010 - NanoTR-VI

Poster Session, Thursday, June 17
Theme F686 - N1123
Comparative Study of Humidity Sensing Properties of PVC-Bt6-Cu and PVC-Bt6-Hg Complex
Films
Mavişe ŞEKER 1 , Salih OKUR 1 , Nesli T. YAĞMURCUKARDEŞ 1 , Gülşah KURT 2 , Bedrettin MERCİMEK 3 , Mahmut KUŞ 4
1Izmir Institute of Technology, Department of Physics Urla/Izmir/TURKEY
2Aksaray University, Department of Chemistry, Aksaray/TURKEY
3 Selçuk University, Department of Chemistry Education, Selçuklu/Konya/TURKEY
4Selçuk University, Department of Chemical Engineering, Selçuklu/Konya/TURKEY
Abstract: This study focuses on respectively the characterization of PVC-BT6-Cu complex and PVC-BT6-Hg complex films coated on a
quartz surface by drop-casting method for humidity detection and comparison of these two thin films properties. The Resistance and quartz
crystal microbalance (QCM) were employed for the characterization. The change of resistance and resonance frequency was monitored with
different increasing and decreasing relative humidity (RH) values between 11% and 97%.The humidity adsorption and desorption kinetics
of the PVC-Bt6-Cu complex and PVC-Bt6-Hg complex films was examined by QCM technique.
Poly(vinyl chloride) (PVC) was modified with
benzoilizotiyosiyanat and amine derivative and PVC
connected benzoylthiourea ligand (PVC-Bt6) was
obtained.Then Cu and Hg complexes of this ligand were
synthesized.[1] In Fig.1 molecular structure of (a) PVC-
Bt6-Cu complex and (b) PVC-Bt6-Hg complex are shown.
CH 2 -CH
CH 2 -CH
CH 2 -CH
CH 2 -CH
20
20
%11
%11 RH
%11
%11 RH
0
0
%22
%22
-20
%43
%43
-20
-40 %53
%53
-60
%75
Cu-PVC
Cu-PVC
-40
%75
(under %84 RH)
%84
%84
-80
%94
-60
%94
-100
Hg-PVC (a) -80
Hg-PVC (b)
%97
(under %84 RH)
-120
200 400 600 800 1000 1200
Time/sec
0 1000 2000 3000 4000 5000 6000
Time/sec
0
dF/Hz
1000
dF/Hz
N
N
N
N
y = 4.1948 * e^(0.032107x) R= 0.98952
100
HN
N
S
O
Cu
S
O
NH
N
HN
N
S
O
Hg
S
O
NH
N
- f(Hz)
Hg
downward
10
Cu
Hg
upward
Cu
(c)
1
20 30 40 50 60 70 80 90 100
Relative Humidity (%)
(a)
Figure 1. (a) Chemical structure of synthesized (a)PVC-Bt6- Cu
complex (b)PVC-Bt6- Hg complex
QCM is a sensor that extremely sensitive to mass changes
in the nanogram scale by measuring the change of
positions of its resonance frequency and it responds to a
given increase of mass simultaneously, regardless of the
species deposited.[2-3] We used in our study QCM with
the model of CHI400A Series from CH Instruments
(Austin, USA) to monitor the change in the resonance
frequency of quartz crystals between gold electrodes
owing to the fact that saturated aquatic solutions which it
was subjected. Relative humidity (RH) values of solutions
were 11%, 22%, 43%, 53%, 75%, 84%, 94% and 97%.
1mg/1ml Cu complex and Hg complex were dissolved in
tetrahidrofuran (THF) solvent and 5μl of solutions were
coated onto QCM thermally evaporated gold electrodes
which has 17μm separation and 120 nm thickness by dropcasting
method. QCM frequency shifts and Resistance
versus Time values were observed depending on relative
humidity with Keitley 2420 Sourcemeter and commercial
humidity-temperature sensor.
(b)
Figure 2. (a) Comparison of QCM frequency shifts of PVC-Bt6-
Cu complex and PVC-Bt6-Hg complex for different increasing
and decreasing RH values.(b) QCM frequency shifts (Hz) as a
function of time (s) for relative humidity values 11% and %84.
(c) The frequency response of PVC-Bt6-Cu and PVC-Bt6-Hg
films covered QCM adsorption-desorption process at fixed point
relative humidity conditions between 11% and 97% RH.
In Fig.2(a) QCM frequency responses of PVC-Bt6-Cu
and PVC-Bt6-Hg comlexes are occured step by step
depending on the different relative humidity conditions
between 11% and %97. In Fig.2(b) We can see QCM
frequency shifts (Hz) as a function of time (s) for relative
humidity values of 11% and %84. The adsorption and
desorption data taken from Fig.2(a) shows an exponential
dependence on relative humidity RH as shown in Fig.2(c).
Fig.2 shows the frequency response of PVC-Bt6-Hg
complex based sensor is more sensitive than PVC-Bt6-Cu
complex based sensor for humidity changes at room
temperature.
*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 Science
and 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