Characterization of Langmuir–Blodgett films of a calix[8]arene and sensing properties towards volatile organic vapors

Abstract

a b s t r a c tWithin this article, we report the characterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[8]arenes. Surface pressure-area isotherms show that very stable monolayers are formed at the air-water interface. The LB film could be deposited onto different substrates which allowed the films to be characterized by UV, quartz crystal microbalance (QCM), surface plasmon resonance (SPR) and atomic force microscopy (AFM). The results indicate that good quality, uniform LB films can be prepared with transfer ratios of over 0.95. QCM results showed that the deposited mass of calix[8]arene monolayer onto a quartz crystal decreased from 693 to 204 ng as the number of layers is increased. AFM studies showed a smooth, and void free surface morphology with a rms value of 1.202 nm. The sensing abilities of this LB film towards the development of room temperature organic vapor sensing devices are also studied. Responses of the LB films to various vapors are fast, large, and reversible. It was found that the obtained LB film is significantly more sensitive to chloroform than other vapors. It can be concluded that this molecule could have a potential application in the research area of room temperature vapor sensing devices.

Conductivity Comparison of Calix[8]arene-MWCNTs Through Spin Coating Technique

“…The direct phase transition from liquid-expanded state to liquid-condensed phase (~1-20 mN/m), followed by solid phase (>20 mN/m) before the collapse were observed. Similar isotherm graphs were observed by others (Çapan et al 2010;Razali et al 2015b). Flexures at around 40 mN/m in C[8]1 isotherm, is similar as reported in others (Davis et al 1996;Ozmen et al 2014).…”

Interaction of para-tert-butylcalix[6]arene molecules in Langmuir films with cadmium ions and their effects on molecular conformation and surface potential

“…[1][2][3][4][5] With such properties, calixarenes have been used in detecting metallic ions, such as alkaline [6][7][8] and alkaline earth [8][9][10] metals, cadmium, [10][11][12] copper, 7,13,14 and for incorporating neutral molecules, [15][16][17][18][19][20] including dopamine, 15 volatile organic compounds 16 and aminoacids. 17 They have also been studied in biological membranes, [18][19][20] and in the formation of molecularly organized films using self-assembled monolayers [21][22][23] and LangmuirBlodgett (LB) [6][7][8][9][10][11][12][13][15][16][17][18][19][20] techniques. These organized films have been applied in metal ion sensors, biosensors, immunosensors and for encapsulating nanoparticles.…”

Langmuir–Blodgett thin film for chloroform detection

“…The refractive index and thickness of different calixarene materials have been determined to have refractive indexes between 1.47 and 1.70 along with thickness values from 0.80 to 1.50 nm [23]. Capan et al [24] studied the refractive index and thickness of calix [8]acid LB films and obtained a refractive index value of 1.21 ± 0.08, along with a thickness value (determined by the slope of the thickness versus layer numbers) to be 1.08 ± 0.07 nm/deposited layer. …”