Scalable Production of Self-Toughening Plant Oil-Based Polyurethane Elastomers with Multistimuli-Responsive Functionalities

Abstract

Plant oils are becoming of high industrial importance due to the persisting challenges befalling with the utilization of fossil fuels. Thus, developing methodologies to produce multifunctional materials by taking advantage of the unique structure of plant oil is highly desired. In this study, castor oil served as a cross-linker and soft segments, by incorporating scalable rhodamine 6G derivatives, to systematically synthesize a series of smart polymers that possess self-toughening and multistimuli-responsive capabilities. The polyurethane elastomers showed 10 times and 60 times increases in tensile strength and toughness, respectively, in comparison with the unmodified polyurethane due to the existence of large amounts of hydrogen bonding, dynamic C−N spiro bonds, rigid benzene ring, and high cross-link densities. The novel polyurethane elastomers exhibited excellent reversible multichromic behaviors in response to light, pH, and mechanics. Notably, the resulting polyurethane elastomers exhibited ultrasensitive sustained photochromism with tunable white emission and rapid reversibility. This study provides a simple and effective strategy to utilize plant oil for multifunctional material preparation and paves the way to open access for application of plant oil-based products in a variety of industry applications, such as sensors, self-fitting tissue scaffolds, and switchable devices.

Polymer Mechanochemistry of Component Parts for Artificial Molecular Machines

“…Because of these properties, Rh has been used in super-resolution fluorescence microscopy. [119] The mechanoisomerization from the closed form to the open form has been demonstrated and utilized mostly in bulk polymeric materials and at interfaces (Figure 4c) [120][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136][137] but not been studied in detail, for example, in a single polymer chain and by theoretical calculations, in addi- tion to insufficient studies on the photoisomerization and thermal isomerization. On the other hand, detailed studies on the mechanochemistry of two Rh-fused mechanophores were conducted recently.…”

Suppressive Photochromism and Promotive Mechanochromism of Rhodamine Mechanophore by the Strategy of Poly(methyl acrylate)/Polyurethane Interpenetrating Polymer Network

“…Mechanophores play an important role as a bridge to connect chemical properties of polymer chains (micromolecular level) with mechanical properties (macromaterial level) of polymeric materials, offering the potential for monitoring strain/stress in everyday situations such as fiber failure, composite fatigue, and coating abrasion. − However, many typical mechanophores, such as spiropyran, − spirothiopyran, , naphthopyran, − rhodamine, − and oxazine, , undergo a response to not only force, but also other stimuli (light, heat, or PH), especially light (Figure ), because molecular design and the structure–property relationships of photochemical molecules established in the literature always serve as a convenient reference for mechanophore exploration . Moreover, for the above photosensitive mechanophores, UV light irradiation is usually a more efficient activation source than force activation.…”