Presentation Type

Poster

Title of Abstract

Modifying Mechanical Properties of Silicon Polymers by Varying Cross Link Densities

Abstract

Combinatorial biomaterials that provide gradients in mechanical stimuli to evaluate cell mechanotransduction will help obtain high throughput data on cell-material interactions, thus propelling research in tissue engineering forward. We intend to fabricate a biomaterial with a spatially controlled gradient in mechanical modulus spanning a physiological range of stiffness using crosslinked networks of polydimethylsiloxane (PDMS), a silicone polymer. Prior to combinatorial material engineering, discrete polymeric samples were prepared by mixing the PDMS base and cross-linking agent in varying ratios from 10:1 to 100:1. Preliminary work involved standardization of parameters such as curing time and temperature for which an organized study was conducted, finally indicating that uniform curing occurred in 4 days at 65⁰C. Specimens were first examined by creep testing to determine whether they were elastic or viscoelastic. Mechanical properties of each sample were then characterized through tensile testing to determine their elastic modulus. Elastic behavior was more dominant in PDMS from 10:1 to 50:1, after which the polymer exhibited viscoelasticity. The elastic modulus varied with crosslink density from 1.5 MPa in 10:1 to 0.018 MPa in 50:1, and thus demonstrated a wide range of tunability in PDMS stiffness.

Categories

Engineering/Physical Science

Research Type

Research Assistant

Mentor Information

Nathan D. Gallant, Ph.D.

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Modifying Mechanical Properties of Silicon Polymers by Varying Cross Link Densities

Combinatorial biomaterials that provide gradients in mechanical stimuli to evaluate cell mechanotransduction will help obtain high throughput data on cell-material interactions, thus propelling research in tissue engineering forward. We intend to fabricate a biomaterial with a spatially controlled gradient in mechanical modulus spanning a physiological range of stiffness using crosslinked networks of polydimethylsiloxane (PDMS), a silicone polymer. Prior to combinatorial material engineering, discrete polymeric samples were prepared by mixing the PDMS base and cross-linking agent in varying ratios from 10:1 to 100:1. Preliminary work involved standardization of parameters such as curing time and temperature for which an organized study was conducted, finally indicating that uniform curing occurred in 4 days at 65⁰C. Specimens were first examined by creep testing to determine whether they were elastic or viscoelastic. Mechanical properties of each sample were then characterized through tensile testing to determine their elastic modulus. Elastic behavior was more dominant in PDMS from 10:1 to 50:1, after which the polymer exhibited viscoelasticity. The elastic modulus varied with crosslink density from 1.5 MPa in 10:1 to 0.018 MPa in 50:1, and thus demonstrated a wide range of tunability in PDMS stiffness.