Matem Erdogan

In the present work, a new macrocycle materials (SB77) was selected and Langmuir-Blodgett thin films of this macrocycle compounds were examined for its vapor sensing capabilities against vapor of aromatic BTX hydrocarbons (benzene, toluene, xylene) through Quartz Crystal Microbalance (QCM) technique. In accordance with this aim, the calix[4]arene LB thin films were prepared onto quartz crystal substrates. The characterization of SB77 LB thin film was performed for nine LB layers fabricated onto the quartz crystal. The frequency shifts and the mass changes for monolayer of these LB thin films were obtained as 32.35 Hz / per layer and 2206.65 ng (8.32 ng mm-2), respectively. All QCM results indicated that SB77 LB thin film chemical sensors exhibits high response, a good sensitivity and selectivity for benzene vapor at saturated or different concentrations than other aromatic hydrocarbon vapors. These LB thin film sensors with SB77 calix [4]arene macrocycle materials have been potential candidates for organic vapor sensing applications with simple and low cost preparation at room temperature.

En tr In this work, the swelling behaviors of the graphene-coated Langmuir-Blodgett (LB) thin films are investigated by using Quartz Crystal Microbalance (QCM) technique. These films were exposed to several Volatile Organic Compounds (VOCs) (acetone, ethanol and methanol) at room temperature to calculate diffusion coefficients of these organic vapors by using the early-time Fick’s law of diffusion. The diffusion coefficients are calculated to be 20.43 x 10−16, 1.30 x 10−16 and 0.91 x 10−16 cm2 s−1 for acetone, ethanol and methanol, respectively. Similar ranking was obtained for the response of graphene-coated QCM sensor as a frequency shift (Δf); acetone (342 Hz) > ethanol (76 Hz) > methanol (51 Hz). Bu çalışmada, grafen kaplı Langmuir-Blodgett (LB) ince filmlerin şişme davranışları Kuartz Kristal Mikrobalans (KKM) tekniği kullanılarak incelenmiştir. Bu filmler, bazı organik buharların (aseton, etanol ve metanol) difüzyon katsayı değerlerinin hesaplanması (Fick’in erken-zaman difüzyon kanunu kullanılarak) için oda sıcaklığında etkileşmeye bırakılmıştır. Difüzyon katsayı değerleri sırası ile aseton, etanol ve metanol için 20.43 x 10−16, 1.30 x 10−16 ve 0.91 x 10−16 cm2 s−1 olarak hesaplanmıştır. Benzer sıralama grafen kaplı KKM sensörünün tepkisi (frekans değişimi, Δf) için de aseton (342 Hz) > etanol (76 Hz) > metanol (51 Hz) olarak elde edilmiştir.

Picoline amide-based calix[4]arene molecule was the first time deposited onto gold substrate as an active layer by using Langmuir-Blodgett (LB) coating technique. UV-visible, atomic force microscopy, and surface plasmon resonance (SPR) technique were used to control monolayer quality. The sensing properties were investigated by exposing the LB thin film to different percentage of organic VOCs vapors such as acetone, benzene, chloroform, ethyl acetate, and methanol in air-VOCs mixture. SPR results showed that this calix[4]arene molecule is a good candidate with a fast and reversible sensor response for VOCs sensing applications.

This study presented that deca pyridin-2-amine bearing Pillar[5]arene (P5-PA) was designed in an appropriate cavity, which acts a part significant role in host–guest interactions of the macrocyclic molecules. P5-PA monolayer was deposited onto suitable substrates as an active layer by using Langmuir-Blodgett (LB) coating technique to examine its vapor sensing capabilities against vapor of some aliphatic hydrocarbons through Quartz Crystal Microbalance (QCM) technique. The kinetic vapor studies were occurred by exposing the P5-PA/LB thin film to different percentage of organic VOCs vapors such as dichloromethane, chloroform and carbon tetrachloride in air-VOCs mixture. The early-time Fick's diffusion law was handled to extract the diffusion coefficients by utilizing QCM data depending real time. It is observed that there were two different regions with two slopes indicating that one belongs to slow surface diffusion and another fast for bulk diffusion into LB thin film. The collected experimental data with 1 Hz sampling frequency was modelled with deep learning models (NARNET and LSTM) which could get satisfactory results on small datasets. The models were trained with 83% samples of data; the remaining 17% data is used to evaluate the developed models prediction performance. The predicted values of models were compared with the original (measured) data in the results section. It is observed from the results; the developed deep learning models have higher than 0.98 correlation coefficient for each vapor, which is satisfactory for prediction applications.

Langmuir–Blodgett (LB) thin films were prepared using an N , N ′-bis( l -alanine tert -butylester)-3,4:9,10-perylene diimide derivative to determine the optimum thin film forming conditions and their sensing properties towards volatile organic vapors.

Graphene oxide (GO) Langmuir-Blodgett (LB) thin films were prepared to use as chemical sensor element. The properties of GO LB thin film layers were characterized via Quartz crystal microbalance (QCM) method. Selectivity of the sensor to various organic vapors was investigated by surface plasmon resonance (SPR) and QCM techniques. Fick’s Equations were used for calculating the diffusion coefficients ( D ) values of organic vapors. It was observed that chemical gas sensing characterictic of the GO film sensor shows a large response to some hazardous organic vapors. Then, by using experimental measurements that obtained during this process, NARX-ANN based mathematical model of frequency shift of the quartz resonator was designed. The results of NARX-ANN verifies the efficiency of the designed model.