Universiti Teknologi Malaysia Institutional Repository

Omnidirectional shape memory effect via lyophilization of PEG hydrogels

Chen, Di and Xia, Xuhui and Wong, Tuck Whye and Bai, Hao and Behl, Marc and Zhao, Qian and Lendlein, Andreas and Xie, Tao (2017) Omnidirectional shape memory effect via lyophilization of PEG hydrogels. Macromolecular Rapid Communications, 38 (7). p. 1600746. ISSN 1022-1336

Full text not available from this repository.

Official URL: http://dx.doi.org/10.1002/marc.201600746

Abstract

Device applications of shape memory polymers demand diverse shape changing geometries, which are currently limited to non-omnidirectional movement. This restriction originates from traditional thermomechanical programming methods such as uniaxial, biaxial stretching, bending, or compression. A solvent-modulated programming method is reported to achieve an omnidirectional shape memory behavior. The method utilizes freeze drying of hydrogels of polyethylene glycol networks with a melting transition temperature around 50 °C in their dry state. Such a process creates temporarily fixed macroporosity, which collapses upon heating, leading to significant omnidirectional shrinkage. These shrunken materials can swell in water to form hydrogels again and the omnidirectional programming and recovery can be repeated. The fixity ratio (R f) and recovery ratio (R r) can be maintained at 90% and 98% respectively upon shape memory multicycling. The maximum linear recoverable strain, as limited by the maximum swelling, is ≈90%. Amongst various application potentials, one can envision the fabrication of multiphase composites by taking advantages of the omnidirectional shrinkage from a porous polymer to a denser structure.

Item Type:Article
Additional Information:RADIS System Ref No:PB/2017/11841
Uncontrolled Keywords:freeze drying, hydrogels
Subjects:R Medicine
Divisions:Biosciences and Medical Engineering
ID Code:66164
Deposited By: Widya Wahid
Deposited On:13 Jul 2017 07:09
Last Modified:13 Jul 2017 07:09

Repository Staff Only: item control page