Paper Number
PO104
Session
Poster Session
Title
Mechanics of elastomer films containing self-assembled smooth and rough colloids
Presentation Date and Time
October 12, 2022 (Wednesday) 6:30
Track / Room
Poster Session / Riverwalk A
Authors
- Yerabati Venkata, Shourie (North Carolina State University, Chemical and Biomolecular Engineering)
- Saraswat, Yug Chandra (North Carolina State University, Chemical and Biomolecular Engineering)
- Hsiao, Lilian (North Carolina State University, Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Shourie Yerabati Venkata, Yug Chandra Saraswat and Lilian Hsiao
Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606
Speaker / Presenter
Yerabati Venkata, Shourie
Keywords
experimental methods; colloids; composite rheology; gels; microscopy
Text of Abstract
Abstract: Synthetic composite elastomers, such as double networks and colloid-laden gels, represent a promising route to mitigate material failure through intrinsic mechanical dissipation and stiffening of constituents. Such types of composite materials typically utilize components with two different size scales to effectively distribute stresses. We synthesize composite poly (dimethyl siloxane)(PDMS) elastomers containing micron-sized rough and smooth colloids. The precursor consists of 21.5% vol PDMS (average Mn - 110,000 g/mol) & sterically stabilized, fluorescent poly(methyl methacrylate)(PMMA) colloids (0.95µm ± 13%) suspended at range of volume fractions between 10%-50% in a continuous phase of hexane and 0.5 vol% tin 2-ethylhexanoate. These constituents are mixed, degassed,& allowed to cure for 20 hours in an air-tight environment. After crosslinking, confocal laser scanning microscopy is used to determine the colloidal microstructure within the PDMS film, with cluster domain sizes on the order of hundreds of microns. We hypothesize that the Young's modulus and fracture energy of the composite PDMS films are dependent on the microstructure of the PMMA colloids and the interlocking of rough particles in close contact with one another. Specifically, when a large strain is applied to the sample, jammed particles are likely to become rotationally hindered causing local stiffening that protects the material against macroscopic rupture. To test this hypothesis, we use a dynamic mechanical analyzer and Instron tester to characterize the tensile properties of the PMMA-PDMS composite films. We will investigate how the bulk mechanics of these films correlate with their microstructural properties and use methods of self- and field-directed assembly to alter the microstructure of the colloidal constituents. Keywords: Elastomers Composites, Rough & Smooth Colloids, Stiffening, Tensile Properties, Microstructure