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High Purity Northwest Inc.

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PM-IRRAS (FTIR)

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The KSV NIMA PM-IRRAS is the first infrared spectrometer made specifically for IR analysis of monolayers floating on an aqueous sub-phase or deposited on reflective substrates. It is a highly sensitive and very surface-specific instrument enabling measurements in ambient conditions. The innovative goniometric configuration allows easy angle adjustment and fast setup.

Features & Benefits

KSV NIMA PM-IRRAS is based on the polarization modulation IR absorption technology that makes it possible to characterize both chemical composition and molecular orientation of even single-molecule thin layers.
Specifically designed for Langmuir film characterization. The system has easy integration with KSV NIMA L & LB Troughs enabling characterization with controlled surface pressure and molecular packing. KSV NIMA PM-IRRAS is suitable for characterizing both floating monolayers on the liquid surface and nanoscale solid surfaces.
The instrument has an user-friendly and open design with simple angle (40°-90°) and height adjustments. It takes only minutes to setup an experiment and easy to combine with external UV light source, heater or other complementary equipment.
The polarization modulation method eliminates background signals from environmental factors such as water vapor and CO2. There is no need for protective gasses or having the optical part of the FTIR spectrometer in vacuum. It also allows longer measurement times, because changes in the light source intensities or water surface height changes do not affect the final spectrum.
The possibility to do transmission measurements.
KSV NIMA PM-IRRAS is a state-of-the-art compact Fourier Transform IR-spectrometer. By positioning the spectrometer and detector on a goniometer above the surface the experimental setup is greatly simplified and provides results within minutes instead of days. The open design allows combined use of other complementary equipment such as external UV light sources and heating. The instrument can be positioned above a fully equipped analytical KSV NIMA Langmuir Trough, facilitating accurate monolayer studies without restrictions.

PM-IRRAS technology allows the measurement of surface specific FT-IR spectra in materials by recording the differences in the reflection of p- and s-polarized light from interfaces enabling detecting chemical compositions and molecular orientation from interfacial films down to films one molecule thick.

Changes in the PM-IRRAS signal intensity and position can be used to analyze chemical composition, molecular absorption/desorption behavior and kinetics, molecular packing, phase transitions, hydration, hydrogen bonding and different surface reactions in a thin film. In addition, in PM-IRRAS the properties of the polarized light can be used to determine the molecular orientation in a film.

Measurement options
Reflectance measurement
In reflectance measurement mode the instrument delivers infrared spectra from an air-water interface or IR-reflective surface. The air-liquid measurement allows observation of any changes in thin film functional groups at the interface. This can be due to structural changes caused by chemical reaction, phase transition or other phenomena. With IR-reflective samples the s-polarization disappears and allows direct access to molecular orientation of the coating. Due to the open design, polymerization reactions on solid surfaces initiated with temperature or UV- light can be easily performed.

Transmittance measurements
Traditional transmittance measurements, such as the study of KBr pellets, are possible due to the flexibility of the goniometer. Measuring non-modulated polarized or non-polarized IRRAS is also possible by turning off the polarization.

Compatibility
The PM-IRRAS software is user friendly and allows you to quickly starting a measurement and to easily save recorded spectra. The software can be operated together with KSV NIMA LB software, allowing collection of IR spectra at strictly defined surface pressures.

Mọi chi tiết vui lòng liên hệ với chúng thôi theo thông tin:
CÔNG TY TNHH VINTEK
Địa chỉ: 280/130 Bùi Hữu Nghĩa, Phường 2, Quận Bình Thạnh, Thành phố Hồ Chí Minh
Điện thoại: 0913146368
Email: vintek-info@vintekco.com

	PM-IRRAS
Hardware
Spectral range (cm-1)	800-4000
Spectral resolution (cm-1)	8
Incident angle adjustment (°)	40-90
Adjustable height	√
ZnSe photoelastic modulator	√
Frequency (kHz)	100
Selectable peak retardation wavelength	√
Instrument dimensions (L×W×H, cm)	73.5×46.1×50.6
Interfaces
Air/water interface	√
IR-reflective solid samples	√
Other IR-reflective surfaces	√

The infrared absorption of the PM-IRRAS is in the range of 800-4000 cm-1, making it possible to detect the following:

Chemical composition of thin films. Chemical composition can be detected from thin films that are just one molecule thick.
Molecular-scale quantitative analysis of molecular orientation. The orientation changes of molecules at the air-water interface or at reflective solids can be detected from the PM-IRRAS peak intensity. This enables, for example, observation of the effect of Langmuir film packing density as well as Langmuir Blodgett coating orientation.
Adsorption/desorption and surface reactions in mono- and multilayers. Studying interaction of biomolecules using cell membrane models can provide means to understand reactions related to drug delivery and the membrane behavior itself. These kinds of model systems are employed in several application areas, such as drug development, food technology, and biological and biochemical research.
Phase transitions in thin films. Monolayer phase transitions can be detected with PM-IRRAS. A typical example would be protein denaturation at the interface or deposited layer.
Hydration/hydrogen bonding. The PM-IRRAS peak position shifts dramatically when the hydration stage changes. This allows the observing of a film’s structural response due to changing external condition such as pH or temperature.

Application examples
Polarization modulated infrared spectroscopy of thin films at the nanometer scale
Precise methods for thin film surface preparation and characterization are key factors in modern nanotechnology. Polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS) is a powerful method for measuring FT-IR from molecules on substrates. From the surface specific IR-spectrum obtained with this method it is possible to deduce chemical composition of films, orientation of molecules and relative amount of material on the surface. This is important in many industrial areas utilizing or planning to utilize nanofabrication and self-assembly, molecular electronics, coatings, corrosives, sensors and catalysis.

PM-IRRAS is an excellent method for FT-IR experiments of nanometer scale thin films. It was possible to acquire FT-IR spectrums of films of around 2 nm thick, and also deduce molecular orientation from the experiments. Linear correlation between LB layer number and peak intensities was found. This demonstrates that the KSV NIMA PM-IRRAS is a powerful tool for thin film characterization and analysis. The measurements are fast and simple to perform thanks to KSV NIMA PM-IRRAS unique design.

Real-time PM-IRRAS study of ultra-thin film photopolymerization
Polymerization kinetics calculated for ultrathin layers of monomers by using data from PM-IRRAS measurements. It should be possible to use the method for other ultrathin monomer film samples that can be prepared on a conductive substrate. In this study it was shown that the obtained kinetic data could be fitted into the regular exponential growth equation of polymerization and it was possible to obtain the activation energy for the epoxy polymerization that corresponded well with known values. The bleaching of porphyrin can also be monitored with the method and it was shown that a polymerized layer bleached slower than a polymerized one