A biodegradable shape-memory nanocomposite with excellent magnetism sensitivity.

This paper reports a kind of biodegradable nanocomposite which can show an excellent shape-memory property in hot water or in an alternating magnetic field with f = 20 kH and H = 6.8 kA m(-1). The nanocomposite is composed of crosslinked poly(epsilon-caprolactone) (c-PCL) and Fe(3)O(4) nanoparticles. The crosslinking reaction in PCL with linear molecular structure was realized using benzoyl peroxide (BPO) as an initiator. The biocompatible Fe(3)O(4) magnetite nanoparticles with an average size of 10 nm were synthesized according to a chemical coprecipitation method. The initial results from c-PCL showed crosslinking modification had brought about a large enhancement in shape-memory effect for PCL. Then a series of composites made of Fe(3)O(4) nanoparticles and c-PCL were prepared and their morphological properties, mechanical properties, thermodynamic properties and shape-memory effect were investigated in succession. Significantly, the photos of the shape-memory process confirmed the anticipatory magnetically responsive shape-recovery effect of the nanocomposites because inductive heat from Fe(3)O(4) can be utilized to actuate the c-PCL vivification from their frozen temporary shape. All the results imply a very feasible method to fabricate shape-memory PCL-based nanocomposites since just a simple modification is required. Additionally, this modification would endow an excellent shape-memory effect to all other kinds of polymers so that they could broadly serve in various fields, especially in medicine.