Cooling induced |
（FYP） Yeo Y
|
|
35% pre-stretched (via DMA) cross-linked EVA
|
|
|
40% pre-stretched
|
Between 30 Deg C water and 90 Deg C water
|
|
Original speed
|
4x speed
|
|
Between 0 Deg C (iced water)-95 Deg C water
|
|
The buckling phenomenon is limited to those polymers with the shape change effect (i.e., cross-linked semicrystalline polymers)
|
|
|
Buckling of shape memory alloy wire in constrained recovery upon thermal cycling
(FYP) Melvern Lee
|
|
Under cyclic Joule heating of SMA wire
|
|
|
Local heating and buckling of SMA spring (kind of torsion bar)
|
|
|
For shape memory alloys, it is rather easy to explain the underline mechanism.
|
|
Heating induced
3D printed (FDM) PLA threads w/wo hair dryer heating
|
|
|
|
Acrylic (PMMA)
PU filament for 3D printing
|
|
|
|
NiTi sputtered atop silicon
|
Water induced
|
|
|
Real time
Comparison of water induced buckling in pre-stretched PEG wire |
|
Further testing:
|
|
|
Ethanol |
PU
|
|
|
Electrospun PU before and after wetting by ethanol
Acetone atmosphere
|
|
|
Acetone (drying) |
|
|
|
Drying induced buckling
（same as that in drying hydrogel films)
（same as that in drying hydrogel films)
Swelling in cellulose fabricYellow: wet/dry; Blue: dry
|
|
|
Quasi-plastic indentation atop pre-compressed
melamine foam A linear system is converted into a non-linear system with multiple stability (bistable structure is a typical case). The maximum local strain in the non-linear system is mostly determined by the local "buckling" deformation.
Ref: Imprinting reversible deformations on a compressed soft rod network Harsh Jain and Shankar Ghosh Soft Matter, 2024, 20, 5053 DOI:10.1039/D4SM00099D |
|
Water baby
|
|
|
Water induced temporary wrinkling atop hydrogel
|
|
|
Shape dependent "buckling" mode: w/wo twisting
|
Evolution of "buckling": twisting then un-twisting
|
|
|
|
Toughgel |
|
|
|
|
|
Water droplet induced wrinkling and drying in air
|
PVA glue |
|
|
|
(marker-pen painted atop)
|
SMA (Nitinol) thin film (sputtered) |
|
|
|
|
|
|
|
|
