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3D‐printed polymer blends with programmable mechanical and compositional heterogeneity were fabricated using grayscale digital light processing by spatially modulating the intensity of light during printing and swelling the resulting part with a second monomer. A rubbery poly(ethylene glycol) diacrylate functionally graded print is variably swollen with acrylamide monomer as a function of crosslinking density. Following a secondary polymerization, a 3D‐printed functionally graded blend with regions of varying composition and stiffness was formed. A deterministic model for polymer conversion informs printing conditions to correspond with predicted material properties based upon local volume fractions of the two materials. Upon the secondary polymerization, two networks are present within the printed structure including glassy and rubbery regions. The compressive moduli of local regions within prints ranges from 76 to 200 MPa and measured moduli of the structures agree with predicted values acquired using finite element analysis. A lattice structure with prescribed local stiffness printed using grayscale exposures deforms differentially when compressed. Advantageously, local dimensional deformations caused by the removal of the unreacted printing monomer are eliminated due to the introduction of the second polymer. This method provides predictive control over local mechanical properties and high shape precision while maintaining the simplicity of vat photopolymerization.
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Exploiting Functionally Graded Elastomeric Materials to Program Collapse and Mechanical Properties
The development of materials with periodic microstructures provides the means to tune mechanical properties via prescribed collapse mechanisms. As investigations give attention to tunable unit cell designs, questions arise regarding strategic ways to exploit built‐up materials to empower large, programmable control over properties and material functionality. The potential to rationally design functionally graded elastomeric materials to yield prescribed mechanical properties is demonstrated herein. Following computational and experimental studies of simplified unit cells and layers, the results inspire ways to exploit linear elastic network analogies to design built‐up and functionally graded materials. This approach exemplifies a streamlined means to create pre‐programmed properties on the basis of simple calculations related to measurements from fundamental material constituents. The results build a foundation for innovative approaches to newly leverage elastomeric materials with programmable collapse for myriad engineering applications.
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- Award ID(s):
- 1738723
- PAR ID:
- 10128022
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Engineering Materials
- Volume:
- 21
- Issue:
- 12
- ISSN:
- 1438-1656
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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