Experimental study of PDMS bonding to various substrates for monolithic microfluidic applications

R. W.R.L. Gajasinghe, S. U. Senveli, S. Rawal, A. Williams, A. Zheng, R. H. Datar, R. J. Cote, O. Tigli

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

This paper presents a comprehensive experimental study and characterization of material and bonding of PDMS based structures to various substrates. A previously published method [1] of bonding is further improved with the inclusion of more substrate material and additional characteristics. Uncured PDMS is used as an adhesive to bond PDMS devices reversibly to various substrates including a number of commonly used substrate materials that are not supported by the widely used plasma treatment method. We have optimized parameters such as PDMS base to curing agent ratio, curing temperature, and PDMS device age to obtain better bond strengths and quality. Bond strengths are presented for semiconductor substrates (silicon, zinc oxide, and silicon dioxide), metals (gold, aluminum), photoresists (SU-8, AZxx) and glass. Silicon based substrates experienced minor amounts of surface residue, but the method is fully reversible for other tested substrates. Bond strengths were measured as maximum endurable pressure between PDMS and substrates. Maximum average bond strengths of more than 0.4 MPa were achieved for substrates with Si-O groups. Other substrates exhibited maximum average bond strengths in the range 0.2-0.3 MPa. Also presented is a method that avoids alignment step for PDMS microfluidic device bonding, named the non-aligned method. This method provides bond strengths of more than 0.1 MPa. Presented methods do not need special equipment or processes such as plasma generators or temperature increases. Biocompatibility tests are performed for materials used in fabrications to ensure applicability in bio-sensing related devices.

Original languageEnglish (US)
Article number075010
JournalJournal of Micromechanics and Microengineering
Volume24
Issue number7
DOIs
StatePublished - Jul 1 2014

Keywords

  • lab on a chip
  • microfluidics
  • PDMS bonding
  • reversible pdms bonding

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering
  • Mechanics of Materials
  • Electronic, Optical and Magnetic Materials

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