Theory 05/Biomaterials
Silk Toughness Is a Two-Phase Ratio
The claim
Spider silk toughness is set by the ratio of crystalline beta-sheet size to amorphous chain length, so neither component alone predicts performance.
01Mechanism
Crystals provide strength while amorphous chains provide extensibility; toughness peaks where the load transfers between them at an intermediate ratio.
02Predictions
- P1Toughness should peak at an intermediate ratio.
- P2Crystallinity alone should mispredict.
03Refutation
Toughness increasing with crystallinity would remove the trade-off.
04Why it resists the grid
The property is a bulk material property that depends on molecular architecture, and the same silk is used for structurally different tasks.