Effect of chain topology on plasmonic properties of pressure sensor films based on poly(acrylamide) and Au nanoparticles

Abstract

Au nanoparticles have been recognized as a colorimetric sensing element in polymeric systems because clustering shifts the red color of individual particles into saturated blue due to distinct plasmonic variation. The mechanism of pressure sensing is based on the disintegration of the particle clusters into the individual particles in polymers upon application of pressure. Polymers are usually composed of linear chains that provide a viscoelastic medium for their diffusion. Changing topology of polymer chains from linear to crosslinked under fixed pressure makes a clear change in spectral features of the particles probably due to the hindrance of particle diffusion by the crosslinking points. Therefore, the working range of the sensor films can be increased to higher-pressure values. In this work, polyacrylamide/Au nanoparticle films were prepared by various concentrations of formaldehyde as a crosslinking agent from 0.5 to 5.0 wt %. The initial absorption signal gradually shifts from 690 to 545 nm for linear chains upon application of pressure while shifting goes down to 571 nm for crosslinked ones. The colorimetric change is also examined under humid environments. Contrary to the crosslinking process, humid environment facilitates the diffusion of particles since the chains swell with water molecules that provide a convenient medium for particle diffusion.

Preparation of Thermosensitive Fluorescent Polyacrylamide Nanofiber Membrane and Visual Temperature Sensing

“…According to the photographs of different concentrations of PAM solutions under a UV lamp, it can clearly be observed that the higher the polymer concentration, the better the fluorescence properties of the solution ( Figure S3 ). The reason is that as the concentration of PAM increases, the viscosity of the spinning solution also increases, the PAM chains increase, and the chains swell with water molecules, which provide a convenient medium for particle diffusion to occur [ 35 , 36 ].…”

Plasmon-induced spectral tunability of Perovskite nanowires

“…1e, the plasmonic characteristics of the Au nanoparticles in a dispersion becomes more distinct and stronger at the wavelength of 520 nm. However, after the plasmonic nanoparticles aggregate in polymeric medium, via increasing the concentration of the plasmonic nanoparticles, strong light absorption is also expected to occur above the wavelength of 520 nm [55,56], which significantly alters the emission dynamics of the interacting NWs. While our measurements confirm that the probability of obtaining clusters of larger sizes from higher Au nanoparticle concentrations is more probable for each sample given in Table 1, the possibility of obtaining larger and more concentrated plasmonic nanoparticle-aggregates, and hence, having a potential of possessing stronger extinction coefficients, dramatically increases from sample 1 to sample 4.…”

Novel silicone-ionic liquid composite with keratin utilized as pressure sensor

“…In recent years, enormous efforts have been made towards improving the performance of pressure sensors. A lot of nanomaterials, including carbon nanotubes [11][12][13][14] , gold/silver nanowires [15][16][17][18] , graphene nanosheets [19][20][21] , metal nanoparticles [22][23] , have been chosen for incorporation with polymers to fabricate novel, more sensitive pressure sensors. Tao et al [19] proposed a graphene-paper pressure sensor that shows excellent performance in the range of 0-20 kPa, and a sensitivity up to 17.2 kPa -1 with a response time of 120 ms. Cho et al [24] presented a flexible capacitive pressure sensor that shows superior pressure sensing performance with a broad sensing range and fast response time.…”