2016/09/07 by Jorge Monreal, Monreal, Jorge, J Schreiber +3
Biochemistry, Genetics and Molecular Biology · Materials Science · #Cellular Mechanics and Interactions #FOS: Physical sciences #Silk-based biomaterials and applications #Soft Condensed Matter (cond-mat.soft) #biodegradable polymer synthesis and properties
paper · pdf · doi:10.48550/arxiv.1609.01803
openalex publication_date 2016/09/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Youngs modulus of soft solids composed of crosslinked synthetic polypeptides has been determined under different conditions. Co-poly-(L-glutamic acid4, L-tyrosine1) [PLEY (4:1)] was crosslinked with poly-L-lysine (PLK) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Elasticity was assessed by subjecting samples to a compressive strain. Cross-linked material at high relative humidity, RH 75-85%, exhibited non-linear elasticity. Stress-strain response was approximately linear at low strain but nonlinear above a threshold strain. Analysis of the secant modulus revealed apparent softening of samples at low strain and hardening at high strain, as in biological soft tissues. Fitting stress-strain data with a neo-Hookean model yielded approximately 40 ≤ E ≤ 300 kPa at high RH. Viscoelasticity was nonlinear at low RH. The average viscosity-driven relaxation time was 13 min at high strain and 6 min at low strain. Analysis of the derivative of the secant modulus for non-linear elastic materials revealed a transient response up to a strain of ε ≈ 0.18-0.20. Above this range, oscillations tended to zero. Non-linear viscoelastic materials showed lower-amplitude oscillations than samples at high RH up to ε ≈ 0.06 and strong damping thereafter. The data suggest that it will be possible to engineer mechanical properties of polypeptide materials.