A review of shape memory polymers based on the intrinsic structures of their responsive switches

Abstract

Responsive switches classification by their intrinsic structures: physical switch and chemical one.

Tunable shape memory properties of highly stretchable poly(ester urea) random copolymers based on α-amino acids

“…(2) The onset of E 0 decrease during glass transition indicates the minimum temperature to actuate molecular chain movements, indirectly reflecting the chain mobility of materials. 14 The semicrystalline A 1.00 V 0.00 and A 0.94 V 0.06 PEUs exhibited a higher temperature corresponding to the onset of the E 0 decrease (hereafter called ''onset temperature'') than the amorphous PEUs (A x V 1Àx , x = 0.72, 0.47, 0.32, and 0.12). We suggested that, the crystalline region suppressed the chain mobility and accordingly led to a higher onset temperature.…”

“…For instance, they could be applied as adjustable scaffolds for bone regeneration, smart dental braces for orthodontic treatment, deplorable stints for vascular engineering, self-tightening sutures for wound healing, drug carriers with controlled release capability, etc. [5][6][7][8][9][10][11][12][13][14] Among all SMPs, heat-stimulated SMPs, also called thermal SMPs, are the most classic type of SMPs. Heatstimulated SMPs are able to transform into one temporary shape or more during shape programming and then recover to the permanent shape under heating.…”

“…In addition, most of the reported SMP biomaterials exhibit a relatively low strain at break (e break , usually below 300%), which greatly limits their practical applications as soft matters. 14,[28][29][30] a-Amino acid-based poly(ester urea)s (PEUs) with high synthetic flexibility and excellent performance show unique advantages as SMPs. [31][32][33][34][35][36][37][38][39][40] The physical properties of PEUs could be manipulated in a wide range by employing various diamine monomers, which were composed of a-amino acid with different pendent groups and diol with different chain lengths.…”

“…In addition, most of the reported SMP biomaterials exhibit a relatively low strain at break ( ε break , usually below 300%), which greatly limits their practical applications as soft matters. 14,28–30…”

Vitrimers trigger covalent bonded bio-silica fused composite materials for recycling, reshaping, and self-healing applications

“…Shape memory or shape memory effect (SME) was the process by which material in a deformed state (temporary shape) was restored to its original state (permanent shape). 53 The SME in polybenzoxazine was generally temperature stimulated and therefore the deformation process takes place at a certain temperature. 54,55 The advantage of developed poly[E-3ap-co-SH(10%)] material exhibits SME without any external stimulation such as temperature.…”