Quantification of internal strain in bent soft materials by a cholesteric liquid crystal elastomer

To develop flexible devices that have mechanical durability, understanding the bending behavior of soft material components is quite important. However, measuring bending strain in soft materials has been limited to their surface due to experimental constraints. In addition to the surface strain analysis, internal strain analysis will further clarify the bending behavior of soft materials. In this study, we quantified internal strain in bending polydimethylsiloxane (PDMS) films, which are a common soft material, through the selective reflection of a cholesteric liquid crystal elastomer (CLCE). The strain analysis with the CLCE revealed that internal strains depend on the position of the bending PDMS films. This internal strain quantification of soft materials leads to the development of flexible devices with high mechanical durability.