Polyisobutylene Film Research Articles

Piezoelectric Vibration Energy Harvesters with Distinct Interdigital Electrodes Used for Toxic Gas Detection and in a Numerical Simulation for a Glucose Sensor Application

Introduction: In this paper, a surface acoustic wave sensor (SAW) for dangerous gas sensing applications has been designed and experimented. The Glucose Sensor applications has been simulated to show that the piezoelectric material has a high significance for use in detection. Background: Detection of gases is one of the major applications SAW gas sensor extend its services into the field of medical and even in power plants. A Surface Acoustic Wave (SAW) is an acoustic wave that propagates on the surface of an elastic material (usually a solid), with an amplitude that decreases with the depth of the substrate. Objectives: SAW devices typically use electrodes on a piezoelectric material to convert an electrical signal to a SAW. Methods: This paper reviews the significance of piezoelectric materials and focuses on MEMS based SAW, and we investigate the resonance frequencies of a SAW gas sensor, which consists of an Inter Digitated Transducer (IDT) etched onto a piezoelectric substrate and covered with a thin Poly Isobutylene (PIB) film. Results: The mass of the PIB film increases as PIB selectivity adsorbs CH2Cl2 (Dichloromethane, DCM) in the air. This causes a shift in resonance to a slightly lower frequency. Conclutions: Our characterization of the piezoelectric material have shown a high significance when a sensitive layer of gas is etch for detected the dangerous gases, we used it in another application Glucose Sensor to show the importance of our system. The sensor of the Glucose Gensor application has been designed and simulated by a finite element analysis which was conducted on LiNbO3 pellets. This model is applied to verify the sensing properties of DCM and the glucose. On the other hand, the Glucose Sensor and the toxic gas detection allow measurement of the concentration,whether it is for the dangerous gases or glucose. The concentration of external glucose and the current density versus glucose concentration were measured by a finite element.

Stretchable battery can power a smart watch

A lithium-ion battery made of gels and composites can be stretched to 1.5 times its original length and still work, even after 1,000-plus tugs, researchers report in a new study ( ACS Nano 2022, DOI: 10.1021/acsnano.1c08405 ). Because all the materials start as pastes, the battery can also be printed directly on fabric, says study coauthor Jeong Gon Son of the Korea Institute of Science and Technology. The new battery is the first in which every part—electrodes, separator, current collectors, and outer cover—is made of intrinsically elastic materials , Son says. The heart of the battery consists of stacked films of an organogel made of poly(vinylidene fluoride) fibers soaked in acetone. To make the cathode, Son and his colleagues add lithium iron phosphate to the gel; to make the anode, they add lithium tin oxide particles. A gel film soaked in electrolyte separates the electrodes from each other. Polyisobutylene films

Finite element simulation of Love wave sensor for the detection of volatile organic gases

The three-dimensional (3D) finite element (FE) simulation and analysis of Love wave sensors based on polyisobutylene (PIB) layers/SiO2/ST-90°X quartz structure are presented in this paper, as well as the investigation of coupled resonance effect on the acoustic properties of the devices. The mass sensitivity of the basic Love wave device with SiO2 guiding layers is solved analytically. And the highest mass sensitivity of 128 m2/kg is obtained as h s/λ = 0.175. The sensitivity of the Love wave sensors for sensing volatile organic compounds (VOCs) is greatly improved due to the presence of coupled resonance induced by the PIB nanorods on the device surface. The frequency shifts of the sensor corresponding to CH2Cl2, CHCl3, CCl4, C2Cl4, CH3Cl and C2HCl3 with the concentration of 100 ppm are 1.431 kHz, 5.507 kHz, 13.437 kHz, 85.948 kHz, 0.127 kHz and 17.879 kHz, respectively. The viscoelasticity influence of the sensitive material on the characteristics of SAW sensors is also studied. By taking account of the viscoelasticity of the PIB layers, the sensitivities of the SAW sensors with the PIB film and PIB nanorods decay in different degree. The gas sensing property of the Love wave sensor with PIB nanorods is superior to that of the PIB films. Meanwhile, the Love wave sensors with PIB sensitive layers show good selectivity to C2Cl4, making it an ideal selection for gas sensing applications.

Effect of surface roughness on film formation properties of screw tightening lubricant PIB

Abstract This paper describes the film formation properties of polyisobutylene (PIB) lubricant under various surface roughness conditions. PIB lubricant has been proposed as a new type of screw tightening lubricant, however the lubrication mechanism in the screw tightening process is yet to be understood. In this study, the in-situ observation tests were conducted under the starved lubrication condition, in which a thin film lubrication regime was simulated. The results showed that film thickness was greater than the surface roughness. Under the high roughness conditions, the time at which direct contact was prevented was shorter. In addition, the occurrence of wear was related to the lambda ratio Λ, and under the high roughness conditions, the friction coefficient increased with time owing to expansion of the wear area. It was also shown that under the fully starved condition, the shear stress did not depend on the shear rate, moreover, its value was constant under all roughness conditions. These results suggest that (i) solid-like PIB film was formed on the contact area under the starved condition and (ii) the formation of a film with a high limiting shear stress potentially inhibits wear. These results were consistent with the results of a tightening test.

Low-temperature dynamics in a dye-doped polymer: correspondence between the data obtained by photon echo and single molecule spectroscopy

Low temperature dynamics (tunneling and vibrational relaxation) in doped polyisobutylene film has been reinvestigated using 2-pulse incoherent photon echo (2IPE) and compared with single-molecule spectroscopy (SMS) data. It has been shown that in a very wide range of low temperatures the 2IPE gives optical dephasing times which correspond to the narrowest zero-phonon lines of single dye molecules.

“Rubbery Stiffening” and Rupture Behavior of Freely Standing Nanometric Thin PIB Films

Prior bubble inflation studies have shown strong evidence of rubbery-like stiffening behaviors for several organic and inorganic thin films. The possible origin is still unclear, but recently Ngai et al. [J. Polym. Sci., Part B: Polym. Phys. 2013, 51 (3), 214−224] and Li and McKenna [Macromolecules 2015, 48 (17), 6329−6336] proposed that the separation of molecular motions and dynamic fragility are closely related to the observed rubber-like stiffening behavior. In the present work, we report observations from bubble inflation measurements on nanometric thin polyisobutylene (PIB) films that test the correlations suggested by the Ngai coupling model (stiffening is related to the shape parameter describing the α-relaxation) and Li and McKenna (the rubbery stiffening correlates with the dynamic fragility). Mechanical properties and surface tension of nanometric thin PIB films were investigated through strain–stress measurements for film thicknesses ranging from 13 to 126 nm. The tests were performed at room ...

Photoinduced smart, self-healing polymer sealant for photovoltaics.

Polyisobutylene (PIB)-based polymer networks potentially useful as smart coatings for photovoltaic devices have been developed. Low molecular weight coumarin functional triarm star PIB was synthesized via a single step SN2 reaction of bromoallyl functional triarm star PIB with 4-methylumbelliferone or umbelliferone in the presence of sodium hydride. Quantitative end functionality was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. UVA (λmax = 365 nm) induced reversible photodimerization of the coumarin moieties resulted in cross-linked elastomeric films exhibiting self-healing behavior. The extent of photodimerization/photoscission was monitored by UV-vis spectroscopy. The low oxygen (1.9 × 10(-16) mol m m(-2) s(-1) Pa(-1)) and moisture (46 × 10(-16) mol m m(-2) s(-1) Pa(-1)) permeability of the cross-linked polymer films suggest excellent barrier properties of the cross-linked polymer films. The self-healing process was studied by atomic force microscopy (AFM). For this, mechanical cuts were introduced in the cross-linked PIB films through micromachining with an AFM tip and the rate of healing induced by UV, sunlight, or both was followed by taking AFM images of the film at different time intervals during the repair process.

Using Plasticizers to Control the Hydrocarbon Selectivity of a Poly(Methyl Methacrylate)-Coated Quartz Crystal Microbalance Sensor

Chemical sensors based on a polymer coated quartz crystal microbalance (QCM) generally present poor molecular selectivity for compounds that contain similar functional groups and possess the same chemical properties. This paper shows for the first time that the selectivity and sensitivity of a poly(methyl methacrylate) (PMMA) based QCM sensor can be significantly enhanced for aromatic hydrocarbons by incorporating a plasticizer into the polymer film. The sensor was fabricated by spin coating PMMA onto a quartz crystal, and the influence of plasticizer type and amount on the response was evaluated. It was shown that the hydrocarbon sensitivity of plasticizer-free PMMA is negligible, while the sensitivity of plasticized PMMA was similar to or in some cases greater relative to highly responsive rubbery polymers such as polyisobutylene (PIB). Detection limits of 4.0, 1.5, 0.4, 0.6, and 0.1 ppm were obtained on a PMMA film containing 25% w/w di(2-ethylhexyl) phthalate for benzene, toluene, ethylbenzene, p-xylene, and naphthalene, respectively. We found that at low plasticizer levels (∼10% w/w) the PMMA film was more sensitive toward ethylbenzene and p-xylene over naphthalene when compared to a PIB film under similar measurement conditions. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) measurements were performed to understand the sensing mechanism, and these studies confirmed a higher hydrocarbon uptake by PMMA in the presence of plasticizer. Positron annihilation lifetime spectroscopy (PALS) studies detected variations in the free volume properties of the polymer films as a function of plasticizer content. The accessible free volume as measured by PALS was significantly less in the PMMA films compared to the PIB, and this result correlates favorably with differences in the QCM response pattern. The QCM results have been rationalized in terms of free volume theory which is responsible for the higher hydrocarbon diffusion/sorption with increased plasticizer content.

A comparative study of DRL-lift and lift on integrated polyisobutylene polymer matrices

This paper presents a comparative study of polymer pixel on sensors obtained by Laser Induced Forward Transfer (LIFT) assisted by a triazene polymer as Dynamic Release Layer (DRL). Polyisobutylene (PIB) was selected as model for chemoselective polymers which could be used as hydrogen-bond acidic polymer for vapor sensors. PIB films deposited on fused silica, respectively, on triazene polymer coated fused silica substrates were used as targets. Both targets were prepared by Matrix Assisted Pulsed Laser Evaporation (MAPLE). The parameters related to a regular, well-defined transfer were analyzed and compared for the substrates with and without the DRL. The morphological characterization of the transferred PIB was performed by Atomic Force Microscopy (AFM), Optical Microscopy, and Scanning Electron Microscopy (SEM). It was found that a minimal thickness of the dynamic release layer, i.e. 100 nm is required to protect the sensitive PIB polymer in a clean laser transfer process.

Thermo- and photooxidation of polyisobutylene. I. Evolutions at temperatures above 50�C

Polyisobutylene films (PIB) were submitted to a thermal oxidation at 100°C and to a photooxidation by exposure to long-wavelength radiations (λ ≥ 300 nm) at 60°C. The modifications of the chemical structure resulting from the oxidation were determined by FT-IR analysis of the polymer films, coupled to chemical treatments that converted specifically the oxidation products. Dissolution of oxidized samples permitted analysis of the polymer by 13C- and 1H-NMR. The structure of the volatile products was determined by mass spectroscopy analysis of the gas phase. Identification of the numerous products formed permitted the proposal of a scheme that accounts for the oxidation of PIB. When the irradiations are carried out at a temperature above 50°C, the depolymerization is favored and the mechanism involves two main routes of oxidation. A direct oxidation starts with the oxidation of radicals obtained by homolysis of the CC bonds on the main chain, and an induced oxidation involves hydrogen abstraction on the methylene and methyl groups by radicals formed by the direct oxidation of the polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1689–1701, 1997

Sensitized photodegradation of polyisobutylene film by addition of tris(α-thiopicolinanilide)–cobalt(III)

The photodegradation of polyisobutylene (PIB) film in air at a temperature where volatile formation is negligible was studied by means of light scattering, chemical actiometry, and spectrophotometric techniques. The degradation is accelerated by addition of tris(α-thiopicolinanilide)—cobalt(III) (TPAC). The sensitization and the course of the degradation were determined by weight-average molecular weight, energy of activation, and quantum yield of the photolysis of the polymer film with 254-nm light. The plots of molecular weight, weight-average chain scission, and degree of degradation vs. irradiation time are linear and confirm the random nature of chain scission of the polymer. The unsaturation produced is proportional to the time of irradiation. Ultraviolet and infrared absorption spectra have been employed to substantiate a mechanism of the degradation process which does not involve hydrogen abstraction from the polymer, but direct cleage of the polymer backbone and addition of initiating radicals of TPAC at the sites of scission.