Paper Number
PO89                         My Program 

Session
Poster Session

Title
Starch granules offer programmable reinforcement and dynamicity to polymer composites

Presentation Date and Time
October 22, 2025 (Wednesday) 6:30

Track / Room
Poster Session / Sweeney Ballroom E+F

Authors (Click on name to view author profile)

  1. Juliano, Shirlaine (University of San Diego, Physics and Biophysics)
  2. Samaniego, Jasmine (University of San Diego)
  3. Lillie, Ian (University of San Diego, Physics and Biophysics)
  4. Iovine, Peter (University of San Diego, Chemistry and Biochemistry)
  5. Robertson-Anderson, Rae M. (University of San Diego, Physics and Biophysics)

Author and Affiliation Lines (in printed abstract book)
Shirlaine Juliano1, Jasmine Samaniego2, Ian Lillie1, Peter Iovine3 and Rae M. Robertson-Anderson1
1Physics and Biophysics, University of San Diego, San Diego, CA 92110; 2University of San Diego, San Diego, CA 92110; 3Chemistry and Biochemistry, University of San Diego, San Diego, CA 92110

Speaker / Presenter 
Juliano, Shirlaine

Keywords
gels; granular materials; rheometry

Text of Abstract
Composites of particles and polymers are widely used in industry due to the increased mechanical tunability afforded by varying particle-polymer interactions and concentrations of the two components. Biological tissues are exemplary particle-polymer composites that exhibit both strength and reconfigurability. Here, we seek to understand the design rules underlying the mechanical properties of tissue-like composites which we engineer by embedding chemically modified starch granules in a gelatin matrix. We measure the bulk linear viscoelastic properties of composites with varying granule concentration and surface chemistry (neutral, waxy, cationic, anionic). We find that increasing granule concentration increases the modulus of all composite types, suggesting reinforcement. However, surprisingly, we also observe increased dissipation likely due to increased transient hydrogen bonding. Finally, examining composites of multiple starch types reveals emergent mechanical properties that are not a simple sum of the constituent composite properties. These results show that tailoring starch chemistry enables more fine-tuned control over the viscoelastic response of particle-polymer composites, suggesting new design strategies for industrial and biomedical applications.