Microwave plasma treatment of polymer surface for irreversible sealing of microfluidic devices

Lab on a Chip ◽  
2005 ◽  
Vol 5 (10) ◽  
pp. 1173 ◽  
Author(s):  
Alex Y. N. Hui ◽  
Gang Wang ◽  
Bingcheng Lin ◽  
Wing-Tat Chan
1989 ◽  
Vol 153 ◽  
Author(s):  
Jihperng Leu ◽  
K.F. Jensen

AbstractIn situ Fourier transform infrared (FTIR) reflection-absorption spectroscopy investigations of etching of thin polyimide and poly(methyl methacrylate) films (200-1500Å) in downstream microwave NF3/O2/Ar plasmas are reported. Etch rates and surface chemistry are monitored as a function of gas phase composition, plasma treatment conditions and time. NF3/Ar plasma treatment leads to significant surface fluorination characterized by the formation of aliphatic fluorine compounds (CFx), acyl fluorides, benzoyl fluoride, and polyfluorinated benzene. Addition of oxygen to the etching gas reduces the degree of surface fluorination and modifies the chemical structure. The absorption bands due to CFx structures decrease gradually while polyfluorinated benzene rings and benzoyl fluoride are absent for NF3/O2 mixtures with more than 20% oxygen. The effect of humidity on the plasma-modified polymers is studied by comparing infrared spectra collected in situ with those after air exposure. For NF3/O2 plasma-treated polyimides significant changes are observed while samples fluorinated in NF3 show no changes after exposure to air overnight. The FTIR data are supplemented by XPS analysis.


1989 ◽  
Vol 154 ◽  
Author(s):  
Jihperng Leu ◽  
K.F. Jensen

AbstractIn situ Fourier transform infrared (FTIR) reflection-absorption spectroscopy investigations of etching of thin polyimide and poly(methyl methacrylate) films (200–1500Å) in downstream microwave NF3/O2/Ar plasmas are reported. Etch rates and surface chemistry are monitored as a function of gas phase composition, plasma treatment conditions and time. NF3/Ar plasma treatment leads to significant surface fluorination characterized by the formation of aliphatic fluorine compounds (CFx), acyl fluorides, benzoyl fluoride, and polyfluorinated benzene. Addition of oxygen to the etching gas reduces the degree of surface fluorination and modifies the chemical structure. The absorption bands due to CFx structures decrease gradually while polyfluorinated benzene rings and benzoyl fluoride are absent for NF3/O2 mixtures with more than 20% oxygen. The effect of humidity on the plasma-modified polymers is studied by comparing infrared spectra collected in situ with those after air exposure. For NF3/O2 plasma-treated polyimides significant changes are observed while samples fluorinated in NF3 show no changes after exposure to air overnight. The FTIR data are supplemented by XPS analysis.


Author(s):  
V. V. Azharonok ◽  
I. I. Filatova ◽  
A. P. Dostanko ◽  
S. V. Bordusov ◽  
Yu. S. Shynkevich

1989 ◽  
Vol 43 (7) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yaoming Xie ◽  
Peter M. A. Sherwood

X-ray photoelectron spectroscopy has been used to monitor the surface chemical changes occurring on type II carbon fibers exposed to air, oxygen, and nitrogen plasmas. In all cases the plasmas caused changes in surface functionality, in terms of both C-O and C-N functionality. Prolonged exposure to the plasmas caused loss of surface functionality for air and oxygen plasmas, and extended treatment caused fiber damage. Plasma treatment of fibers promises to be an effective method of fiber treatment.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 580
Author(s):  
Chao-Ching Chiang ◽  
Philip Nathaniel Immanuel ◽  
Yi-Hsiung Chiu ◽  
Song-Jeng Huang

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.


2020 ◽  
Vol 992 ◽  
pp. 658-662
Author(s):  
M.A. Mokeev ◽  
L.A. Urkhanova ◽  
A.N. Khagleev ◽  
Denis B. Solovev

Mechanical, chemical and plasma treatment are the main kind of treatment of polytetrafluoroethylene (PTFE) films. Each method is different from each other by the adhesive force: the value of the wetting angle. Mechanical treatment allows different particles to permeate into the structure of the polymer. Chemical treatment creates new functional groups on the polymer surface, but this method is toxic and dangerous. Plasma treatment, in a glow discharge non-thermal plasma, is a more ecological and practical method. The experiment showed that the plasma treatment successfully increases the adhesion, this has been proven by infrared spectroscopy and scanning electron microscopy. According to the obtained data of the wetting angle, the regression equation was derived. A graphical model is constructed by regression equations allows you to determine the main processing factor and choose the optimal values of treatment.


Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1067 ◽  
Author(s):  
Aya E. Abusrafa ◽  
Salma Habib ◽  
Anton Popelka

Herein, the surface treatment of polyurethane (PU) films via air, O2, N2, Ar, and their mixtures were tested. The treatment was performed to incorporate new polar functionalities on the polymer surface and achieve improved hydrophilic characteristics. The PU films were subjected to RF low-temperature plasma treatment. It was found that plasma treatment immensely enhanced the hydrophilic surface properties of the PU films in comparison with those of the pristine samples; the maximum plasma effect occurred for the PU sample in the presence of air plasma with treatment time of 180 s at nominal power of 80 W. The surface topography was also found to vary with plasma exposure time and the type of gas being used due to the reactivity of the gaseous media. Roughness analysis revealed that at higher treatment times, the etching/degradation of the surface became more pronounced. Surface chemistry studies revealed increased O2 and N2 elemental groups on the surface upon exposure to O2, N2, air, and Ar. Additionally, the aging study revealed that samples treated in the presence of air and Ar were more stable in comparison to those of the other gases for both the contact angle and peel test measurements.


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