A new approach to fabricate PDMS structures using femtosecond laser

Hamsapriya Selvaraj

doi:10.32920/ryerson.14644545.v1

Abstract

Polydimethylsiloxane (PDMS) is commonly used to prototype micro and nano featured components due to its beneficial properties. PDMS based devices have been used for diverse applications such as cell culturing, cell sorting and sensors. Motivated by such diverse applications possible through pure PDMS and reinforced PDMS, numerous efforts have been directed towards developing novel fabrication techniques. Prototyping 2D and 3D pure and reinforced PDMS microdevices normally require a long curing time and must go through multiple steps. This research explores the possibility of fabricating microscale and nanoscale structures directly from PDMS resin using femtosecond laser processing. This study offers an alternative fabrication route that potentially lead to a new way for prototyping of pure and reinforced PDMS devices, and the generation of hybrid nanomaterials. In depth investigation of femtosecond laser irradiation of PDMS resin reveals that the process is highly intensity-dependent. At low to intermediate intensity regime, femtosecond laser beam is able to rapidly cure the resin and create micron-sized structures directly from PDMS resin. At higher intensity regime, a total break-down of the resin material occurs and leads to the formation of PDMS nanoparticles. This work demonstrates a new way of rapid curing of PDMS resin on a microsecond timescale using femtosecond laser irradiation. The proposed technique permits maskless single-step curing and is capable of fabricating 2D and 3D structures in micro-scale. Reinforced PDMS microstructures also have been fabricated through this method. The proposed technique permits both reinforcement and rapid curing and is ideal for fabricating reinforced structures in microscale. The strength of the nanofiber reinforced PDMS microstructures has been investigated by means of Nanoindentation test. The results showed significant improvement in strength of the material. Hybrid PDMS-Si and hybrid PDMS-Al nanoparticle aggregate were generated using femtosecond laser. The results indicate that the hybrid PDMS nanostructures are clusters of nanoparticles that agglomerate and interweave three-dimensionally and also the possibility of formation of Si/Al nanoparticles enclosed in PDMS Shells. Presence of PDMS in the final hybrid structure is confirmed by micro-raman analysis. The versatility of our technique opens a new pathway to generate hybrid 3D fibrous nanostructures on any materials.

Highlights

1. 1 Biomedical micro-device materials and fabricationMicro devices, often referred to as micro electro mechanical systems (MEMS), have traditionally been fabricated from silicon-based materials using processing techniques adapted from the semiconductor industry
6.3 Summary When irradiation laser intensity is high above the ablation threshold of PDMS resin, direct vaporization occurs and PDMS resin was converted into nanoparticles
Material characterization showed that the formed nanoparticles have the same chemical composition and characters as PDMS resin

Summary

Introduction

Often referred to as micro electro mechanical systems (MEMS), have traditionally been fabricated from silicon-based materials using processing techniques adapted from the semiconductor industry. S.Mackowski [126] demonstrated a method to design novel hybrid nanostructure comprising biological photosynthetic systems (natural photosynthetic protein–pigment complexes) and nanostructures which includes semiconductor nanocrystals, metallic nanoparticles or carbon nanotubes. These hybrid structures enhances the efficiency of light harvesting either via Plasmon excitation in metals or absorption tunability characteristics of semiconductors. Such hybrid systems, through combining the properties of the constituents, provide a novel paradigm for designing photovoltaic devices. The detection sensitivity for SEB is nanogramme per milliliter level

Objectives

Methods

Conclusion