본 연구에서는 미세유체 시스템 제작에 적합한 3D 프린팅 방식 및 소재 별 표면특성 분석을 통해 각 응용 사례에 적합한 프린터 및 소재 선정에 가이드라인을 줄 수 있는 기초 연구를 수행하였다. 가장 보편적으로 사용되는 적층 방식과 해상도가 상대적으로 높은 광경화 방식에 대해 프린팅 방식과 소재에 따른 표면 특성을 살펴보았다. 적층 방식의 프린트물은 소재에 무관하게 후처리 전에는 친수성 특성을 보이나 아세톤 증기에 의한 후처리 후에는 소수성 특성을 보임을 확인할 수 있었다. SEM을 이용한 표면 조도 관찰을 통해 이러한 접촉각의 변화가 후처리에 의한 표면의 결 구조의 제거에 기인한 것임을 확인하였다. 광경화식 프린트물은 적층식 대비 친수성의 특성을 보였으나 소수성 코팅을 이용해 표면 개질이 가능함을 실험적으로 확인하였다. 두 프린팅 방식 중 투명한 재질이 요구되는 경우, 적층 방식은 투명한 시편을 만드는 것이 불가능함을 확인하였으며 광경화 방식의 경우 충분한 투명도가 확보됨을 확인하였다. 액적 접촉충전 현상에 기반한 디지털 전기천공 시스템의 electroporation chip을 광경화 방식으로 제작하였으며 성공적으로 전기천공을 시연함으로써 미세유체 시스템에 직접 적용이 가능함 또한 확인하였다.

In this study, basic research was conducted to provide guidelines for selecting printers and materials suitable for each application case by analyzing 3D printing method and surface characteristics of materials suitable for microfluidic system. We have studied the surface characteristics according to the materials for the two typical printing methods: The most commonly used method of Fused Deposition Modeling (FDM) printing and the relatively high resolution method of Stereolithography (SLA) printing. The FDM prints exhibited hydrophilic properties before post - treatment, regardless of the material, but showed hydrophobic properties after post - treatment with acetone vapor. It was confirmed by the observation of surface roughness using SEM that the change of the contact angle was due to the removal of the surface structure by post-treatment. SLA prints exhibited hydrophilic properties compared to FDM prints, but they were experimentally confirmed to be capable of surface modification using hydrophobic coatings. It was confirmed that it is impossible to make a transparent specimen in the FDM method. However, sufficient transparency is secured in the case of the SLA method. It is also confirmed that the electroporation chip of the digital electroporation system based on the droplet contact charging phenomenon was fabricated by the SLA method and the direct application to the microfluidic system by demonstrating the electroporation successfully.

3D printing Microfluidics Contact angle Surface roughness Transparency

Almada-Lobo F, J. Innov. Manag., 3(4), 16 (2015)
Maynard AD, Nat. Nanotechnol., 10(12), 1005 (2015)
Duballet R, Baverel O, Dirrenberger J, Autom. Constr., 83, 247 (2017)
Gross BC, Erkal JL, Lockwood SY, Chen C, Spence DM, Anal. Chem., 86(7), 3240 (2014)
Bhatia SN, Ingber DE, Nat. Biotechnol., 32, 760 (2014)
Rupal BS, Garcia EA, Ayranci C, Qureshi AJ, J. Interg. Design & Process Sci., 1-16(2018).
Waheed S, Cabot JM, Macdonald NP, Lewis T, Guijt RM, Paull B, Breadmore MC, Lab Chip, 16(11), 1993 (2016)
Chen C, Mehl BT, Munshi AS, Townsend AD, Spence DM, Martin RS, Anal. Methods, 8(31), 6005 (2016)
Ho CM, Ng SH, Li KH, Yoon YH, Lab Chip, 15(18), 3627 (2015)
Sochol RD, Sweet E, Glick CC, Venkatesh S, et al,, Lab Chip, 16(4), 668 (2016)
Kitson PJ, Rosnes MH, Sans V, Dragone V, Cronin L, Lab Chip, 12, 3267 (2012)
Im DJ, Noh J, Moon D, Kang IS, Anal. Chem., 83(8), 5168 (2011)
Im DJ, Ahn MM, Yoo BS, Moon D, Lee DW, Kang IS, Langmuir, 28(32), 11656 (2012)
Im DJ, Yoo BS, Ahn MM, Moon D, Kang IS, Anal. Chem., 85, 4038 (2013)
Choi CY, Im DJ, Korean Chem. Eng. Res., 54(4), 568 (2016)
Yang SH, Im DJ, Langmuir, 33(48), 13740 (2017)
Im DJ, Jeong SN, Yoo BS, Kim B, Kim DP, Jeong WJ, Kang IS, Anal. Chem., 87(13), 6592 (2015)
Im DJ, Korean Chem. Eng. Res., 56(1), 79 (2018)
Im DJ, Jeong SN, Biochem. Eng. J., 122, 133 (2017)
Kurita H, Takahashi S, Asada A, Matsuo M, Kishikawa K, Mizuno A, Numano R, PLOS ONE, 10(12), e01442 (2015)
Kim YH, Kwon SG, Bae SJ, Park SJ, Im DJ, Bioelectrochemistry, 126, 29 (2019)
Yoo BS, Im DJ, Ahn MM, Park SJ, Kim YH, Um TW, Kang IS, Analyst, 143(23), 5785 (2018)
Kim YH, Im DJ, Algal Research, 35, 388 (2018)
Gao H, Kaweesa DV, Moore J, Meisel NA, JOM, 69(3), 580 (2017)
Prajitno DH, Maulana A, Syarif DG, J. Phys.: Conference Series, 739, 012029 (2016)