Poly(ε‐caprolactone)‐based shape memory polymers with variable polydimethylsiloxane soft segment lengths

Abstract

Thermoresponsive shape memory polymers (SMPs) are stimuli-responsive materials that return to their permanent shape from a temporary shape in response to heating. The design of new SMPs which obtain a broader range of properties including mechanical behavior is critical to realize their potential in biomedical as well as industrial and aerospace applications. To tailor the properties of SMPs, “AB networks” comprised of two distinct polymer components have been investigated but are overwhelmingly limited to those in which both components are organic. In this present work, we prepared inorganic-organic SMPs comprised of inorganic polydimethyl-siloxane (PDMS) segments of varying lengths and organic poly(ε-caprolactone) (PCL) segments. PDMS has a particularly low Tg (−125 °C) which makes it a particularly effective soft segment to tailor the mechanical properties of PCL-based SMPs. The SMPs were prepared via the rapid photocure of solutions of diacrylated PCL40-block-PDMSm-block-PCL40 macromers (m = 20, 37, 66 and 130). The resulting inorganic-organic SMP networks exhibited excellent shape fixity and recovery. By changing the PDMS segment length, the thermal, mechanical, and surface properties were systematically altered.

Porous inorganic–organic shape memory polymers

“…The thermomechanical properties of solid PCL-based SMPs have been modified by introduction of organic hard [4,28–30] or soft [31,32] segments whose T g ’s are higher and lower than that of PCL ( T g = −60 °C), respectively. Recently, we reported a new class of inorganic-organic solid SMPs prepared via the photochemical cure of acrylated (AcO) macromers containing inorganic polydimethylsiloxane (PDMS) soft segments and organic PCL switching segments of varying lengths (AcO-PCL n block -PDMS m - block -PCL n -OAc) [33,34]. Because the T g of PDMS (−125 °C) [35] is much lower than that of PCL, its ability to modulate mechanical properties is quite effective.…”

Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold

“…R f has been previously observed to be slightly greater than 100 % 14,27 due to a slight increase in compressive strain during shape fixation from the recrystallization of PCL segments into more compact structures 27 . An increase in R r values has been previously noted for solid 28,29,22 and porous SMPs 13,14,23 . It is thought that during the first cycle, residual strain originating from processing is removed such that shape recovery increases in the next cycle 7 .…”

Shape Memory Systems with Biodegradable Polyesters

“…Zhang et al [45] produced diacrylated PCL-polydimethylsiloxane-PCL macromers that have been photocured afterward. This development targeted the reduction of water sensitivity and improvement of the flexibility and surface properties of the polymer whereby maintaining the switch function of the PCL phase (Ttrans=80 o C).…”