PNIPAM: a thermo-activated nano-material for use in optical devices

Abstract

In this paper we describe the use of thermoactivated PNIPAM nano-material in optical switching devices. In other publications, the PNIPAM is used either as a carrier for crystalline colloidal array self-assemblies or as micro-particles that serve as pigment bags. In this publication we use a simpler-to-fabricate pure PNIPAM solution in a semi-dilute regime. The PNIPAM devices produced are transparent at temperatures below a critical temperature of 32°C and become diffusing above this temperature. We show that at 632 nm the transmission through the devices is about 75% in the transparent state while the additional attenuation achieved in the diffusing state is of the order of 38 dB. The experimental fall and rise times obtained are large (about 300 ms and 5 s, respectively) due to the non-optimised thermal addressing scheme. In addition, spectral measurements taken in the infrared spectrum (700-1,000 nm) demonstrate that the cell response is flat over a large portion of the infrared spectrum in both the transparent and the diffusing states.

Adsorption of Phosgene Gas on Pristine and Copper-Decorated B12N12 Nanocages: A Comparative DFT Study

“…Discovery of nanotubes (carbon nanotubes) by Ijimia increased the demand for nanoscale materials and laid the foundation for the rapid development of the field of nanoscale materials (carbon nanoscale materials) . Nanomaterials such as nanocages, nanoclusters, and nanotubes find vast applications in optical devices, , catalysis, sensing materials (sensors), adsorption, , and medical and electronic devices …”

Rehydration of Thermoresponsive Poly(monomethoxydiethylene glycol acrylate) Films Probed in Situ by Real-Time Neutron Reflectivity

“…20 Many of the previously formed hydrogen bonds will be broken, and the polymer chain conformations will switch from a swollen state to a collapsed state. Because of this special LCST type behavior, a large variety of applications are emerging, such as drug delivery systems, 26,27 valves to control liquid transfer, 28 artificial muscles, 29 microfluidics, 30 optical switching, 31 and smart textiles. 32−34 Until now, investigations about thermoresponsive polymers with LCST-type behavior have focused on poly(N-isopropylacrylamide) (PNIPAM).…”

“…Many of the previously formed hydrogen bonds will be broken, and the polymer chain conformations will switch from a swollen state to a collapsed state. Because of this special LCST type behavior, a large variety of applications are emerging, such as drug delivery systems, , valves to control liquid transfer, artificial muscles, microfluidics, optical switching, and smart textiles. − Until now, investigations about thermoresponsive polymers with LCST-type behavior have focused on poly­( N -isopropyl­acrylamide) (PNIPAM). ,, PNIPAM features a sharp transition behavior as well as a LCST in an experimentally easily accessible range of about 32 °C, which exhibits an exceptionally weak dependence on molar mass and concentration . As a consequence, various applications of PNIPAM arise in the field of biomedicine .…”

Structure and Thermal Response of Thin Thermoresponsive Polystyrene-block-poly(methoxydiethylene glycol acrylate)-block-polystyrene Films

“…2 In particular, the collapse transition of polymers with a lower critical solution temperature (LCST) behavior is interesting for a large variety of applications, such as drug delivery systems, 22−24 valves to control liquid transfer, 25,26 or optical devices. 27,28 However, so far, most of the investigations have focused on polymer solutions and on bulk polymer samples. 29−33 Compared to these bulk hydrogel samples, thin hydrogel films can swell and collapse only in one direction (along the surface normal), which makes them promising for applications like nanosensors and nanoswitches.…”