Linear/network poly(ε-caprolactone) blends exhibiting shape memory assisted self-healing (SMASH)

Erika D. Rodriguez, Xiaofan Luo, Patrick T. Mather

Research output: Contribution to journalArticle

258 Scopus citations

Abstract

Self-healing (SH) polymers are responsive polymeric materials that can repair mechanical damage such as cracks in an autonomous fashion. In most SHpolymers studies reported to date, crack closure was either unaddressed or achieved by manual intervention. Here, we report a new strategy that utilizes shape memory (SM) to prepare novel SH polymers that are capable of simultaneously closing and rebonding cracks with a simple thermal trigger.This strategy, termed "shapememory assisted self-healing (SMASH)", is demonstrated in a blend system consisting of cross-linked poly(ε- caprolactone) network (n-PCL) with linear poly(e-caprolactone) (l-PCL) interpenetrating the network, and exhibits a combination of SM response from the network component and SH capacity from the linear component. Thermomechanical analysis revealed that the thermoset, n-PCL, demonstrates reversible plasticity;a form of shape memory where large plastic deformation at room temperature is fully recoverable upon heating. This SM action assists to close any cracks formed during deformation and/or damage while l-PCL chains tackify the crack surfaces by diffusion to the free surface and ultimately across the area of damage during the same heating step as used for SM. In our study, we investigated the controlled damage and SMASH healing of blends with varying composition using tensile testing of essential work of fracture film specimens. The healing component, l-PCL used had a high M w (M w ̃65k g/mol) to enable reentanglement after diffusion across the interface while the shape memory component, n-PCLwas prepared fromPCL telechelic diacrylates and a tetrathiol cross-linker, yielding excellent shape memory. We found excellent self-healing of films by the SMASH mechanism, with near complete healing for l-PCL contents exceeding 25 wt %. Applications are envisioned in the area of self-healing bladders, inflated structure membranes, and architectural building envelopes.

Original languageEnglish (US)
Pages (from-to)152-161
Number of pages10
JournalACS Applied Materials and Interfaces
Volume3
Issue number2
DOIs
StatePublished - Feb 23 2011

Keywords

  • Reversible plasticity
  • SMASH
  • Self-healing
  • Shape memory

ASJC Scopus subject areas

  • Materials Science(all)

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