Patent Application
20080063811
Next, a plasma ignition gas is introduced (Step 104). That is, a plasma ignition gas is introduced into an atmosphere plasma equipment to ignite the plasma. In a preferred embodiment, at this time, the plasma is used to clean the surface of the substrate, such that the surface of the substrate is made to generate active free radicals. In one embodiment, the plasma ignition gas includes air, nitrogen gas, argon gas, oxygen gas, helium gas or a mixture of the above two or more gases. The plasma ignition gas is mainly used to ignite the plasma. After that, the resulted plasma gas bombards the surface of the substrate, so as to clean the surface of the substrate, and meanwhile make the surface of the substrate generate active free radicals.
Next, the surface modifying precursor is heated (Step 106). The surface modifying precursor is evaporated to gas after being heated. The temperature for heating the surface modifying precursor is between 150° C. and 200° C. In another embodiment, if the surface modifying precursor has a low boiling point, the surface modifying precursor does not need to be heated. Furthermore, the surface modifying precursor may be solid, liquid, gas or powder. Particularly, the surface modifying precursor is selected from fluorosilane, polysiloxane and a combination thereof. The ratio of the fluorosilane to the polysiloxane is, for example, between 1 and 0. To be more specific, the surface modifying precursor may use fluorosilane independently. The surface modifying precursor may use polysiloxane independently. In addition, the surface modifying precursor may be a mixture of fluorosilane and polysiloxane, and the ratio of fluorosilane to polysiloxane is 0.1:99.9-99.9:0.1, and preferably 80:20-99.9:0.1.
In an embodiment, the fluorosilane contains 1-17 fluorine atoms. The fluorosilane is, for example, F8261 (fabricated by Falcone Corporation), C16H19F17O3Si, CF3C2H4—Si(OCH3)3. In another embodiment, the fluorosilane includes fluoralkylsilane, for example, fluoroalkyl group-containing trichlorosilane, fluoroalkyl group-containing trialkoxysilane, fluoroalkyl group-containing tricyloxysilane, fluoroalkyl group-containing triisocyanatesilane, or fluoroalkyl group-containing acrylatesilane.
Furthermore, the molecular weight of the polysiloxane is between 200 and 20000. In an embodiment, the polysiloxane is, for example, 1107 (fabricated by Dow Corning Corporation), and the chemical formula is as shown in (1),
In another embodiment, the polysiloxane is, for example, polydimethylsiloxane or derivatives thereof, wherein the chemical formula of the derivative is as shown in (2),
wherein a, b=0-10, preferably 0-5; X, Y respectively represent hydroxyl group, amino group, epoxy group, ether group, ester group, unsaturated carbon-carbon double bond group, halogen atom or a combination thereof, n=1-100.
Particularly, it should be noted that, if the surface modifying precursor uses the mixture of the fluorosilane and the polysiloxane, the fluorosilane and the polysiloxane may be premixed and then introduced into the equipment for the atmosphere pressure plasma process, or they may be introduced into the equipment for the atmosphere pressure plasma process respectively.
Next, the carrier gas is used to carry the gas of the surface modifying precursor into the atmosphere plasma equipment (Step 108). In an embodiment, the carrier gas includes air, nitrogen gas, argon gas, oxygen gas, helium gas or the mixture of the above two or more gases. In this manner, the gas of the surface modifying precursor may be dissociated into free radical molecules of the surface modifying precursor in the atmosphere plasma equipment. The free radical molecules of the surface modifying precursor are chemically bonded with the active free radicals on the surface of the substrate to form a film layer on the surface of the substrate. The thickness of the film layer is, for example, between 5 nm and 1000 nm.
The film layer formed above has hydrophobic, lipophobic, or hydrophobic and lipophobic characteristics depending upon the type and ratio of the used surface modifying precursor. For example, if the used surface modifying precursor is fluorosilane, the surface of the substrate processed by the atmosphere pressure plasma process has hydrophobic and lipophobic characteristics. If the used surface modifying precursor is polysiloxane, the surface of the substrate processed by the atmosphere pressure plasma process has hydrophobic characteristic. If the used surface modifying precursor is the mixture of fluorosilane and polysiloxane, the surface of the substrate processed by the atmosphere pressure plasma process has hydrophobic and lipophobic characteristics.
It should be noted that, if the used carrier gas adopts an oxygen-containing gas (for example, air, oxygen gas or a mixing gas of oxygen gas and nitrogen gas), the carrier gas is helpful for igniting and generating the plasma. In this manner, the process for forming the film layer on the surface of the substrate is accelerated. Furthermore, the present invention is not limited to performing the atmosphere pressure plasma process on a specific surface of the substrate, that is, the atmosphere pressure plasma process is performed on one, two, or two or more of the above surfaces of the substrate according to practical requirements.
In an embodiment, the method of forming the film layer on the surface of the substrate is, for example, to use an atmospheric pressure plasma jet (APPJ) equipment as shown in
Definitely, the present invention is not limited to using the APPJ equipment to perform the surface process on the substrate, and other atmosphere plasma equipments may also be used, for example, the dielectric barrier discharge equipment or the corona discharge equipment.
After the film layer has been formed on the surface of the substrate, referring to
Several examples are illustrated below to illustrate that the surface characteristic is adjusted to be hydrophobic, lipophobic, or hydrophobic and lipophobic, after the substrate is processed by the atmosphere pressure plasma process of the present invention.
In the fourth example, a mixture of poly(dimethylsiloxane) (PDMS for short), bis(3-aminopropyl) terminated and 1H,1H,2H,2H-perpfuorodecyltriethoxysilane (FAS for short) is used as the surface modifying precursor. The weight ratio of PDMS:FAS is 95:5. After this surface modifying precursor is used to perform the surface modifying on the substrate through the APPJ equipment, the water contact angle obtained after being tested by the ASTM C 813-90 method is 101 degrees, and the oil contact angle is 53 degrees. The transparency obtained after being tested by the transparency test of ASTM D 1747-97 is 93%. The water contact angle obtained after being tested by the adhesion test of ASTM D 3359-95 is 100 degrees. The water contact angle obtained after being tested by the abrasion test under a pressure of 500 g/cm2 is 91 degrees.
In the fifth example, PDMS and FAS are used as the surface modifying precursor, with the weight ratio of PDMS:FAS as 97:3. After this surface modifying precursor is used to perform the surface modifying on the substrate through the APPJ equipment, the water contact angle obtained after being tested by ASTM C 813-90 is 75 degrees, and the oil contact angle is 31 degrees. The transparency obtained after being tested by the transparency test of ASTM D 1747-97 is 93%. The water contact angle after being tested by the adhesion test of ASTM D 3359-95 is 72 degrees. The water contact angle obtained after being tested by the abrasion test under a pressure of 500 g/cm2 is 71 degrees.
In the sixth example, PDMS is used as the surface modifying precursor, that is, the weight ratio of PDMS:FAS is 100:0. After this surface modifying precursor is used to perform the surface modifying on the substrate through the APPJ equipment, the water contact angle obtained after being tested by the ASTM C 813-90 method is 69 degrees, and the oil contact angle is 27 degrees. The transparency obtained after being tested by the transparency test of ASTM D 1747-97 is 93%. The water contact angle obtained after being tested by the adhesion test of ASTM D 3359-95 is 68 degrees. The water contact angle obtained after being tested by the abrasion test under a pressure of 500 g/cm2 is 63 degrees.
To sum up, the atmosphere pressure plasma process is adopted in the present invention to adjust the surface characteristic of the substrate, which does not require a large quantity of solvent, and the processing time is relatively short. The method of the present invention is suitable for continuous production.
In addition, the surface modifying precursor used in the present invention provides the surface of the substrate with hydrophobic, lipophobic, or hydrophobic and lipophobic characteristics.
Furthermore, the atmosphere plasma equipment used by the present invention may perform the surface modifying on the substrates with different shapes and made of different materials, so it can be widely applied. That is to say, besides the surface modifying process performed on flat substrates (for example, the glass plate, the plastic cloth, and the textile product), the atmosphere plasma equipment also can be used in the surface process performed on complex fine molds, and screw parts.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 95133848 | Sep 2006 | TW | national |
