UV sensor based on polyurethane foam

Abstract

Ultraviolet light (UV) present in solar radiation has an important effect on the health of human skin. For that reason, we developed a disposable and easy-to-manufacture UV light sensor based on surface color change of a polyurethane (PU) film and examined its performance against radiation received from a lamp or from the sun. The chemical modification after UV exposition and the consequent color variation from light yellow to brown in PU sensor were studied by using RGB image analysis and a reflectance prototype containing an Arduino board. It was found that the photochemical modification of PU films increases absorption of visible radiation in the blue spectrum range. Furthermore, PU surface was more sensitive to UV (<390) than that found in visible light when exposed to sunlight, which was associated with the presence of a chromophore in the material modified. In addition, it was found that the extract obtained from irradiated PU showed its maximum absorption at 309 nm. Hence, the use of this economical light radiation sensor seems to be a very promising tool to determine exposure to UV light from the solar spectrum.

Original antifouling strategy: Polypropylene films modified with chitosan‐coated silver nanoparticles

“…This behavior was attributed to the fact that a higher content of carboxylate groups at the surface led to a higher adsorption of AgNP/CS complexes driven by electrostatic interaction with the ammonium groups of the CS chain. In addition, the error bar of the band ratio becomes significantly larger when the grafting degree increases, since roughness and inhomogeneity of film surface rise too …”

“…The PP/RM/glass system was subsequently placed inside a photoreactor at 20 cm of distance (UV irradiance near 12 w m −2 ) from a UV lamp centered on top. This light source (NNI 40/20 35 W, UV Consulting Peshl, Spain) has a length of 25 cm with a UV total power 188 W m −2 determined using a measurement method developed in our research team . The reaction starts when the UV light (254 nm) passes through the PP film, which interacts with the BP molecule close to the PP surface.…”

Stretchable and Highly Sensitive Flexible Strain Sensor Based on a Three‐Layer Core–Shell Structure of Polydopamine/Polypyrrole@Natural Rubber for Human Activity Monitoring

“…Compared to traditional sensors, flexible strain sensors have excellent flexibility, portability, and stretchability. [14][15][16][17][18][19] Typically, they are constructed using conductive sensing materials combined with elastomeric substrates, [11,20] such as polyurethane, [21,22] polydimethylsiloxane (PDMS), [16,23,24] natural rubber (NR), [25,26] and so on. The most commonly used strain sensing materials include carbon nanomaterials (carbon black, [24] carbon nanotubes, [27] and Mxene, [28,29] ), metal nanomaterials (silver nanowires [30] and silver nanoparticles [31] ), and intrinsic conducting polymers such as polyaniline (PANI), [32] polypyrrole (PPy), [33] and poly (3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS).…”