印章特性和印刷压力对微接触印刷工艺的影响

微接触印刷（μCP）是一种能在微纳米尺度上完成表面图案化的技术，主要特点是高效和低成本．研究了μCP过程中印章机械特性和印刷压力对形成的微图案质量的影响．为了进一步分析聚二甲基硅氧烷（PDMS）制作的印章特性，浇注了5种配比的PDMS试样，并进行了单轴拉伸和压缩试验，获得了其应力应变关系．制作了3种配比的表面线型图案印章，实施微接触印刷使其印刷压强在1kPa～1MPa．通过图形化分析对最终的微接触印刷质量进行评估．实验结果表明：最优的压强区间为20～200kPa．较小的压力将会产生印章与基底的间隙，而较大的压力将会导致印章的严重变形．由于质量比为20：1的PDMS印章的弹性模量最小，其在中等压力下的微接触印刷质量最好，而较硬的印章可有效地抵抗印刷中产生的变形．

Effects of Stamp Properties and Printing Pressure on Microcontact Printing Process

Microcontaet printing （μCP） is a highly efficient and low-cost technology for surface pattern- ing in micro/nano scale. The effects of stamp mechanical properties and printing pressures on the quality of fabricated micropatterns during μCP process were investigated. To study the polydimethylsiloxane （PDMS） based stamps, five mass ratios of PDMS specimens were fabricated, then their uniaxial tension and compression testing experiments were conducted, and the relationship between stress and stain was gained. Three line-pattern stamps with different mass ratios were cast when the printing pressure was ap- plied within the range from 1 kPa to 1 MPa. The printing quality was assessed by graphic analysis. Ex- perimental results demonstrate that the optimal pressure is within the range from 20 kPa to 200 kPa. Low- er pressure causes larger defects due to the confined space for patterning, while larger pressure leads to the deformation of stamps. The results also show that the stamp of 20：1 mass ratio can obtain the highest quality of the printed patterns under medium level pressure due to its lowest Young＇ s modulus. Hard stamp can be effective in resisting some deformations during printing.