電漿聚合對二甲苯與傳統聚對二甲苯薄膜之保固特性

Protective Performance of Plasma-polymerized Para-xylene and Conventional Parylene Coating

聚對二甲苯薄膜（Parylene coating）用於材料表面改質以達阻水、耐酸鹼、防蝕及提高生醫材料表面之生物相容性等用途已行之多年，但習知之真空熱裂解製程起始原料（Dipara-xylene dimmer）昂貴且耗時耗能。先前的研究已成功使用價廉之液態對二甲苯（Paraxylene）為起始原料，並利用脈衝直流電源製備電漿聚合對二甲苯（Plasma-polymerized paraxylene, PPPX）鍍膜。本研究乃藉由比較兩者之表面及機械保護特性，進而了解PPPX是否可替代Parylene coating用於材料表面改質。研究結果發現，具結晶性之Parylene coating從截面剝斷面觀察為纖維狀軟性鍍膜，鍍膜附著性佳，百格附著性為5B，但膜較軟，鉛筆硬度為6B，鍍膜呈微疏水性，水滴接觸角為86.1°。PPPX則為非晶性，從截面剝斷面觀察無任何微觀特徵，且在不同單體流量或脈衝電源頻率下所得之鍍膜皆呈高附著性，百格附著性介於4B到5B之間，鍍膜硬度高，鉛筆硬度為8H，且疏水性較高，水滴接觸角介於98.5~ 121.1°之間。從機械特性比較結果可知，PPPX比Parylene coating具有更佳的機械防護力，故應可成為應用於電子工業及生醫材料等表面防護之低價格製備的另一種選項。

Parylene coatings have been widely used in surface modification for more than six decades because they bear properties of being water proof, resistance to acidic and alkaline solutions, anticorrosion, and improving biocompatibility of biomedical materials. Conventional deposition processes for preparing parylene coatings have drawbacks of requiring expensive starting materials, being time consuming, and consuming a relatively high amount of energy. Our previous work successfully engineered a pulsed-dc plasma-polymerized deposition system by using low-cost liquid para-xylene as a starting material for preparing plasma-polymerized para-xylene (PPPX) films. This study aims at comparing the surface characteristics and mechanical protective performance of parylene coatings and PPPX films. The results showed that the crystallinicparylene coating exhibited afibrous appearance in the cross-sectional SEM image, good film adhesion (cross-cut adhesion of grade 5B), low film hardness (pencil hardness of grade 6B), and mild hydrophobicity (a water contact angle of 86.1°). In contrast, PPPX films were amorphous, featureless in cross-sectional view, of good film adhesion (cross-cut adhesion of grade4B to 5B), robust (pencil hardness of grade 8H), and more hydrophobic (water contact angles of 98.5 to 121.1°). In summary, PPPX films could provide better mechanical protection than parylene coatings and may be considered as an alternative for surface modification in industries of electronics and biomedical materials.