A Poly(dimethylsiloxane) Microfluidic Channel Coated with Poly-p-xylylene for Nanocrystal Growth Applications : 나노입자 성장을 위한 Poly-p-xylylene이 코팅된 Poly(dimethylsiloxane) 미세유체 장치

다국어 초록 (Multilingual Abstract)

Applications of microfluidic device fabricated in poly(dimethylsiloxane) (PDMS) have been limited to water-based analysis rather than nonpolar solvent based chemistry due to PDMS swelling problem occurring by absorption of the solvents. The absorption and swelling causes PDMS channel deformation in shape and changes the cross sectional area, making it difficult to control the flow rate and concentrations of solution in PDMS microfluidic channels. We propose that poly-p-xylylene polymers (parylenes) were chemical vapor deposited on the surfaces of PDMS channels to alleviate the effect of solvents on the absorption and swelling. The parylene coated surface sustains 3hours with a small volumetric change (less than 22% of PDMS swelling ratio). By generating an air-nonpolar solvent interface based on droplets in PDMS channel, we confirmed poly-p-xylylene coated PDMS microfluidic channels have the potential to be applicable to nanocrystal growth using nonpolar solvents.

국문 초록 (Abstract)

Poly(dimethylsiloxane) (PDMS)로 만들어진 미세유체 장치는 무극성용매가 PDMS 내부에 흡수되어 PDMS의 부피를 팽창시키는 성질 때문에 무극성용매를 사용하는 화학분야에 적용이 어렵다. 이러한 PDMS의 흡수와 팽창하는 특성은 PDMS 미세유체 장치의 내부변형과 단면적의 변화를 일으켜서, PDMS 미세유체 장치 내에서의 유체 제어와 용액의 농도 조절을 어렵게 한다. 우리는 무극성용매에 의해 발생하는 PDMS의 흡수하고 팽창하는 정도를 감소시키기 위해 비다공성 성질을 가진 poly-p-xylylene (parylene)을 증기 화학 증착법으로 코팅한 PDMS 미세유체 장치를 제안한다. Parylene이 코팅된 PDMS 표면은 무극성용매인 톨루엔 환경내에서 낮은 부피 변화(코팅이 되지 않은 PDMS의 팽창률 보다 22% 낮음)로 약 3시간동안 본래의 형태를 유지한다. PDMS 미세 유체 채널 내에 방울 기반의 공기-무극성용매 계면을 발생시킴으로써, poly-p-xylylene이 코팅된 PDMS 미세 유체 장치가 무극성용매를 사용하는 나노입자 성장 분야에 응용 가능성을 보여준다.

목차 (Table of Contents)

• I. INTRODUCTION 1--
• 1.1 Motivations 1--
• 1.2 Objectives and Problem 3--
• 1.3 Hypothesis 6--
• 1.4 Background Information 7--
• 1.4.1 Microfluidic platforms 7--
• II. MATERIALS AND METHODS 8--
• 2.1 Microfluidic Devices 8--
• 2.1.1 PDMS microfluidic chip fabrication (Paper based master) 8--
• 2.1.2 PDMS microfluidic chip fabrication (Photolithography) 9--
• 2.2 Parylene-C film on PDMS Surfaces 10--
• 2.2.1 Parylene-C coating 10--
• 2.2.2 Thickness and porosity measurements 12--
• 2.2.3 Swelling measurements 12--
• 2.2.4 Air-nonpolar solvent interface formation 13--
• 2.3 Gold Nanoparticle Synthesis 14--
• 2.3.1 Materials 14--
• 2.3.2 Synthesis of nanoparticles in water 16--
• 2.3.3 Phase transfer of nanoparticles to hexane 16--
• 2.3.4 2D self-assembly of gold nanoparticles 19--
• III. RESULTS AND DISCUSSION 21--
• 3.1 Swelling of Millimeter Scale PDMS Pieces in Hexagonal Shape 21--
• 3.2 Swelling of PDMS Microfluidic Channel 24--
• 3.3 Droplet based An Air-nonpolar Solvent Interface 27--
• IV. CONCLUSION 29--
• 4.1 Conclusion 29--
• REFERENCES 30