A Processable Shape Memory Polymer System for Biomedical Applications

作者：Hearon Keith; Wierzbicki Mark A; Nash Landon D; Landsman Todd L; Laramy Christine; Lonnecker Alexander T; Gibbons Michael C; Ur Sarah; Cardinal Kristen O; Wilson Thomas S; Wooley Karen L; Maitland Duncan J^*

来源：Advanced Healthcare Materials, 2015, 4(9): 1386-1398.

DOI：10.1002/adhm.201500156

• biomedical devices
• polyurethane
• shape memory polymers
• structure-property relationships
• thiol-ene " click" chemistry

Polyurethane shape memory polymers (SMPs) with tunable thermomechanical properties and advanced processing capabilities are synthesized, characterized, and implemented in the design of a microactuator medical device prototype. The ability to manipulate glass transition temperature (T-g) and crosslink density in low-molecular weight aliphatic thermoplastic polyurethane SMPs is demonstrated using a synthetic approach that employs UV catalyzed thiol-ene click reactions to achieve postpolymerization crosslinking. Polyurethanes containing varying C=C functionalization are synthesized, solution blended with polythiol crosslinking agents and photoinitiator and subjected to UV irradiation, and the effects of number of synthetic parameters on crosslink density are reported. Thermomechanical properties are highly tunable, including glass transitions tailorable between 30 and 105 degrees C and rubbery moduli tailorable between 0.4 and 20 MPa. This new SMP system exhibits high toughness for many formulations, especially in the case of low crosslink density materials, for which toughness exceeds 90 MJ m(-3) at select straining temperatures. To demonstrate the advanced processing capability and synthetic versatility of this new SMP system, a laser-actuated SMP microgripper device for minimally invasive delivery of endovascular devices is fabricated, shown to exhibit an average gripping force of 1.43 +/- 0.37 N and successfully deployed in an in vitro experimental setup under simulated physiological conditions.

• 出版日期2015-6-24