KY Space Grant GF-21-010: Mechanical Behavior of Bonded PDMS for Microfluidics in Microgravity

Mechanical behavior of bonded PDMS for microfluidics in microgravity ABSTRACT On Earth, the development of microfluidic or Lab-on-a-Chip (LOC) technology has been of particular interest in the miniaturization of biological and chemical problems. Microfluidic systems are advantageous over macroscale counterparts due to their efficient automation, low cost, easy integration, and lower mass. These advantages allow microfluidics in components for spaceflight purposes by manipulating the flow of minuscule volumes of liquids through carefully arranged microscale channels. However, microfluidic systems must be characterized on Earth’s conditions first before perfecting microfluidics in space applications. A common material used for microfluidic devices is Polydimethylsiloxane (PDMS). PDMS is cost-effective, biocompatible, permeable, and easily replicates nanostructures. However, some disadvantages of using PDMS are the absorption of molecules aggravated in favorable pH, swelling on many solvents leading to unwanted channel deformations, and its inherent hydrophobic nature 1. Although the advantages outweigh the shortcomings of PDMS, careful mitigation strategies must be explored to create an efficient PDMS-based microfluidics system and enhance its durability as a mechanical backbone. The objectives of this project are: (i) evaluate bonding or crosslinking of substrates with PDMS; (ii) develop an appropriate method for bonding and crosslinking of PDMS substrates; (iii) characterize the effects of bonding and crosslinking on the mechanical behavior of the PDMS films using microindentation. We propose investigating bonded PDMS''s structural integrity with substrates such as untreated glass, metal, thermoplastics, and coatings. The anticipated results will help tailor and understand the mechanical behavior of bonded PDMS to create an efficient microfluidic system and control its structural integrity. We aim to prolong microfluidics systems'' life cycle to tackle precise experimental conditions in microgravity. 1. Raj M, K. & Chakraborty, S. PDMS microfluidics: A mini review. Journal of Applied Polymer Science 137, 48958 (2020). 1