• Journal of Adhesion and Interface
• /
• v.19 no.4
• /
• pp.154-162
• /
• 2018

Plasma treatment and corona treatment have been used for surface modification of polydimethylsiloxane (PDMS) film by activating its surface with the -OH group. Adhesion promoter or coupling agent was also used to improve adhesion of PDMS film with various materials. However, obtained hydrophilicity onto the surface of PDMS films with those processes was transient and vulnerable. In this study, a new alkoxysilane-functionalized acrylic polymer precursor was first synthesized by copolymerization process, and then was reacted with HO-terminated PDMS through condensation reaction to prepare a new surface modifier for PDMS film. The structure and molecular weight of the prepared surface modifier were confirmed by 1H-NMR and GPC measurement. Surface properties of surface modifier-coated PDMS films were also investigated by using XPS, ATR and WCA analysis. The adhesion between the PDMS film and the surface modifier was tested using cross-cut test.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.2
• /
• pp.181-184
• /
• 2006

Nd:YAG($\lambda$=266 nm, pulse) laser beam was irradiated on the PDMS surface to improve its chemical reaction, wettability, adhesive property. The various surface modification methods of PDMS were already studied using oxygen plasma, ozone and corona discharge. The surface modification using laser has the advantage of the simple experiment that only directly irradiated laser beam on the PDMS surface in the air. After the laser treatment, the PDMS surface was investigated using a contact angle measuring instrument. The contact angle was decreased with a increase of the surface oxygen content. In conclusion, the wettability of PDMS surface was improved by the laser treatment without changing of its bulk characteristics.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.15 no.5
• /
• pp.321-327
• /
• 2022

In this paper, a wrinkled structure was formed on the PDMS surface through UV/Ozone treatment, and the wrinkle structure formation mechanism was revealed through physicochemical characterization. A wrinkle structure was formed on the PDMS surface through UV/Ozone treatment for 30 min, and periodic wrinkle formation on the PDMS surface was confirmed by cross-sectional imaging of the scanning electron microscope. In addition, through x-ray photoelectron spectroscopy spectral analysis, it was confirmed that the silica-like-surface of SiOx on the PDMS surface was formed by UV/Ozone. The results of this study not only improve the understanding of the mechanism of wrinkle structure formation on the PDMS surface by UV/Ozone treatment, but also can be used as a basic study to adjust the amplitude and period of the wrinkle structure according to UV/Ozone irradiation conditions in the future.contact angles and the surface energies of FSAMs, it was confirmed that pretilt angles of LC molecules increased according to the alkyl chain length. High optical transparency and uniform homeotropic LC alignment characteristics of FSAMs showed the possibility of FSAMs as an LC alignment layers.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.1
• /
• pp.38-42
• /
• 2015

Polydimethylsiloxane (PDMS) is a widely used material for replicating micro-structures because of its transparency, deformability, and easy fabrication. At the nanoscale, however, it is hard to fill a nanohole template with uncured PDMS. This paper introduces several simple methods by changing the surface energy of a nanohole template and PDMS elastomer for replicating 100nm-scale structures. In the case of template, pristine anodic aluminum oxide (AAO), hydrophobically treated AAO, and hydrophillically treated AAO are used. For the surface energy change of the PDMS elastomer, a hydrophilic additive and dilution solvent are added in the PDMS prepolymer. During the molding process, a simple casting method is used for all combinations of the treated template and modified PDMS. The nanostructured PDMS surface was investigated with a scanning electron microscope after the molding process for verification.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.223-223
• /
• 2012

Surface engineering plays a significant role in fabricating highly functionalized materials applicable to industrial and biomedical fields. Surface wrinkles and folds formed by ion beam or plasma treatment are buckling-induced patterns and controlled formation of those patterns has recently gained considerable attention as a way of creating well-defined surface topographies for a wide range of applications. Surface wrinkles and folds can be observed when a stiff thin layer attached to a compliant substrate undergoes compression and plasma treatment is one of the techniques that can form stiff thin layers on compliant polymeric substrates, such as poly (dimethylsiloxane) (PDMS). Here, we report two effective methods using plasma modification techniques for controlling the formation of surface wrinkles and folds on flat or patterned PDMS substrates. First, we show a method of creating wrinkled diamond-like carbon (DLC) film on grooved PDMS substrates. Grooved PDMS substrates fabricated by a molding method using a grooved master prepared by photolithography and a dry etching process were treated with argon plasma and subsequently coated with DLC film, which resulted in the formation of wrinkled DLC film aligning perpendicular to the steps of the pre-patterned ridges. The wavelength and the amplitude of the wrinkled DLC film exhibited variation in the submicron- to micron-scale range according to the duration of argon plasma pre-treatment. Second, we present a method for controlled formation of folds on flat PDMS substrates treated with oxygen plasma under large compressive strains. Flat PDMS substrates were strained uniaxially and then treated with oxygen plasma, resulting in the formation of surface wrinkles at smaller strain levels, which evolved into surface folds at larger strain levels. Our results demonstrate that we can control the formation and evolution of surface folds simply by controlling the pre-strain applied to the substrates and/or the duration of oxygen plasma treatment.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.4
• /
• pp.142-144
• /
• 2004

To use Poly-dimethylsiloxane (PDMS) for the electrokinetic flow channel, the PDMS surface must be modified to be hydrophilic. With $O_2$ plasma treatment, it is difficult to maintain hydrophilicity for more than one day. In this paper, we present the chemical modification of the PDMS surface using 2-Hydroxyethyl methacrylate (HEMA) to prolong hydrophilicity lifetime. The oxide radicals generated temporarily on the PDMS surface by $O_2$ plasma are grafted with HEMA. Once the PDMS samples have been grafted, they demonstrate improved hydrophilicity retainment and electroosmotic flow characteristics compared to the untreated PDMS and the oxidized PDMS following the $O_2$ plasma process. This phenomenon was verified by the contact angles, Fourier transform infrared (FTIR) spectra and electro osmotic flow rates observed for more than 300 hours.

• Transactions on Electrical and Electronic Materials
• /
• v.3 no.4
• /
• pp.10-15
• /
• 2002

Surface states of polydimethylsiloxane (PDMS) treated by plasma were investigated by the analysis by x-ray photoelectron spectroscopy (XPS) and surface voltage decay. Plasma treatment causes the silica-like(SiO$\_$x/, x=3∼4) oxidative layer, which is confirmed with XPS, and lowers surface resistivity from 1.78$\times$1014 Ω/square to 1.09$\times$10$\^$13/ Ω/square with increasing the plasma treatment time. By measuring the decay time constant of surface voltage, the calculated surface resistivity was compared with the value directly measured by a voltage-current method, so good agreement between two methods was obtained. It was observed that the plasma treatment led to decrease of the thermal activation energy of the surface conduction from 31.0 kJ/mol of untreated specimen to 21.8 kJ/mol. It is found that our results allow the examination of effects of plasma on electrical properties of PDMS.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1480-1481
• /
• 2008

In this paper, we present surface treatments for achieving bonds between PMMA and PDMS substrates. Silane primer is used for the formation of hydroxyl group on PMMA surfaces. The formed hydroxyl groups enhance the bonding strength of PDMS-PMMA substrates without channel clogging and structure deformation. The bonding strength on the different surface treatments (include oxygen plasma, 3-APTES, and corona discharge) is evaluated to find optimal bonding condition. The maximum bonding strength at the optimal surface treatment is over 300 kPa. The surface treatment using silane primer can be used to the bonding process of Micro-TAS and Lab-on-a-Chip.

• Membrane Journal
• /
• v.19 no.1
• /
• pp.54-62
• /
• 2009

Pervaporation membrane for butanol separation was prepared by hybrid process. Plasma treatment of commercial poly(dimethylsiloxane) (PDMS) membrane was attempted and combination of plasma treatment and PDMS solution coating on polysulfone, poly(ether imide) supports were also performed. Plasma treatment of PDMS membrane with hexane and silane group compounds was performed to increase the hydrophobicity of the surface, which enhanced the separation factor upto 12.5 at the expense of flux decrease down to $1.15kg/m^2{\cdot}hr$. Contact angle and relative sorption ratio were also related with hydrophobicity of the memrbane. Increase of PDMS prepolymer composition resulted in dense structure of coating layer with better separation factor. Effects of sequence of PDMS coating vs. plasma treatment were examined. It was found that plasma treatment with butanol and n-hexane plasma followed by PDMS coating showed better performance and vice versa for plasma treatment with hexamethyldisilane and hexamethyldisilazane.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.11a
• /
• pp.169-169
• /
• 2015

Poly(dimethysiloxane, PDMS)은 그 다양한 사용분야 때문에 지속적으로 연구분야에서 연구주제가 되고 있었다. 본 논문에서는 산소 플라즈마 처리에 의한 PDMS/기판에서의 접착강도를 peel 테스트를 통하여 정량적으로 측정하였다.