Thermoplastic Polyurethane‐Based Stimuli‐Responsive Nanocomposites: A Review on Self‐Healing and Shape Memory Properties
Ramya Devi, Piyush Gupta, Chandra Khatua, Kinsuk Naskar, Santanu Chattopadhyay
Abstract
ABSTRACT Stimuli‐sensitive polymer composites are sensitive to environmental factors such as temperature, pH, and electric and magnetic fields; they are studied immensely with technological applications. Stimuli‐sensitive polymer composites encompass shape memory polymer composites, self‐healable composites, and 4D printed composites, exhibiting a wide transition temperature range. The application of thermoplastic polyurethane (TPU) shows exceptional recovery qualities post‐deformation. The phase‐separated, unique segmented structure of TPU (soft and hard segments) enables an impressive recoverable strain of up to 400%, implying outstanding flexibility and tuneable physical properties. Such properties render it an ideal candidate for flexible electronics, shape‐memory materials, sensors, and self‐healing polymers. The synergistic interaction between the matrix and nanofillers substantially enhances the sensitivity and functionality of the composite. This review highlights the current state of the art and some of the most promising applications of stimulus‐sensitive TPU‐based nanocomposites, including shape memory‐assisted self‐healing (SMASH), focusing on recent advancements in biomedical devices, wearable electronics, and environmental sensing. Additionally, it discusses the mechanisms that govern self‐healing and shape memory, highlighting how nanofillers are critical for performance improvement. These nanocomposites with augmented stimuli‐responsive behaviors, in addition to the inherent properties of TPU, are expected to lead to pervasive technological changes across a wide range of applications.