A stretchable e-textile was fabricated by simply soaking Spandex fabric in a conductive polymer aqueous dispersion, PEDOT-PSS. The resulting conductive fabric had an average conductivity of 0.1 S/cm. Subjecting the fabric to more than one soaking step increased the conductivity of the fabric up to ca. 2.0 S/cm resulting in a 33% faster switching speed. This simple methodology is not limited to Spandex (50% nylon/50% polyurethane). Several other fabric compositions were investigated for their conductivity via this process, including 100% cotton, 60% cotton/40% polyester, 95% cotton/5% Lycra, 60%polyester/40% rayon, 100% polyester, and 80% nylon/20% Spandex, listed in order of decreasing hydrophilicity. Those fabrics with higher water uptake resulted in higher conductivities upon soaking in PEDOT-PSS. Electrochromic polymers coated on the fabric could be switched between their different colored states, even upon stretching of the Spandex. SEM revealed that the electrochromic polymer coated on the substrate separated under stretching, uncovering the color of the base conducting fabric. It was found that the PEDOT-PSS was not a film on the Spandex but rather homogenously dispersed nanoparticles within the fabric matrix forming a percolated network.

This review is focused on the materials and methods used to fabricate closed-loop systems for type 1 diabetes therapy. Herein, we give a brief overview of current methods used for patient care and discuss two types of possible treatments and the materials used for these therapies–(i) artificial pancreases, comprised of insulin producing cells embedded in a polymeric biomaterial, and (ii) totally synthetic pancreases formulated by integrating continuous glucose monitors with controlled insulin release through degradable polymers and glucose-responsive polymer systems. Both the artificial and the completely synthetic pancreas have two major design requirements: the device must be both biocompatible and be permeable to small molecules and proteins, such as insulin. Several polymers and fabrication methods of artificial pancreases are discussed: microencapsulation, conformal coatings, and planar sheets. We also review the two components of a completely synthetic pancreas. Several types of glucose sensing systems (including materials used for electrochemical, optical, and chemical sensing platforms) are discussed, in addition to various polymer-based release systems (including ethylene-vinyl acetate, polyanhydrides, and phenylboronic acid containing hydrogels).

Herein we describe the preparation and characterization of reflective-type electrochromic devices using stretchable, conductive fabric electrodes. Two fabrics were used in this study: woven stainless steel mesh and Lycra spandex impregnated with a conducting polymer (poly [3,4-ethylenedioxythiophene]-poly[styrene sulfonate], PEDOT-PSS). Electrochromic polymers were prepared on the surface of these fabric electrodes and devices were assembled. The time taken for the electrochromic polymer to switch between colored states in devices prepared with stainless steel electrodes (conductivity ca. 9,800 S/cm) was ca. 0.3 s, whereas that using PEDOT-PSS loaded Lycra (conductivity ca. 0.1 S/cm) was a few seconds. The iris effect was evaluated for each of the device architectures, showing no effect for steel mesh/steel mesh devices and a propagating front for spandex-based devices. The electrochromic spandex functioned in solution while being stretched. In addition, stenciled devices were built. Such fabric electrochromic devices represent a critical step toward the realization of totally chameleonic fabric.