Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods

Abstract

We employ two approaches to tune the properties of concurrently inscribed volume polarization and surface relief gratings in nanocomposite thin films containing the azopolymer PAZO (poly[1-4-(3-carboxy-4-hydrophenylazo)benzensulfonamido]-1,2-ethanediyl, sodium salt]) and goethite (α-FeOOH) nanorods. The first one is applied on the stage of sample preparation by varying the concentration of the goethite nanorods from 0% to 15%. Then, different angles between the recording beams are set in the holographic scheme, which allow us to obtain gratings with spatial periods in the range from 0.86 to 2.51 µm. Surface relief modulation close to 300 nm is achieved as well as total diffraction efficiency in the ±1 diffracted orders of more than 50%. The influence of the incorporated goethite nanorods on the properties of both volume birefringence and the surface relief grating are discussed.

Blending Approach Preparation of PVA-g-PMA Films with Embedded “Green” Synthesized Silver Nanoparticles for Acetone Optical Detection

“…It is seen from Figure 6 b that there is an optimal concentration, over which the swelling degree significantly drops. The existence of an optimal concentration is in accordance with the results of other authors [ 36 , 37 , 38 ] and could be explained by the reinforcement of the polymer matrix due to the increased amount of AgNPs. When AgNP concentration increases, the polymer matrix becomes more rigid.…”

“…Similar results of swelling enhancement in nanoparticle-doped photopolymers were obtained in [ 36 , 37 , 38 ]. The authors studied the formation of surface relief grating in a light-sensitive photopolymer and obtained a considerable increase of surface relief in photopolymers doped with Au nanoparticles with different sizes ranging from 10 to 50 nm [ 36 ] as compared to the undoped polymer.…”

“…The authors explained the increase with the additional free volume introduced in the polymer matrix through embedding nanoparticles that facilitated the free movement of azo chromophores [ 36 ]. It is interesting to note that a similar enhancement was also obtained when a photopolymer was doped with ZnO NPs [ 37 ] or goethite (-FeOOH) nanorods [ 38 ]. Therefore, a conclusion can be drawn that the observed effect of swelling improvement is common and it is not inherent to a particular type of nanoparticle.…”

Hybrid Dispersion Model Characterization of PAZO Azopolymer Thin Films over the Entire Transmittance Spectrum Measured in the UV/VIS/NIR Spectral Region

“…Thus, toxic organic solvents, which are usually required for film deposition of other azopolymers, can be avoided. Furthermore, the water solubility of PAZO allows for easy preparation of photoanisotropic nanocomposite layers containing PAZO and nanoparticles such as silver and gold nanoparticles [ 14 , 15 ], goethite nanorods [ 16 ], biologically active metal complexes [ 17 ], etc. These nanocomposite materials show enhanced photo response, higher birefringence, increased diffraction efficiency and higher surface relief modulation compared with non-doped polymer.…”

“…These nanocomposite materials show enhanced photo response, higher birefringence, increased diffraction efficiency and higher surface relief modulation compared with non-doped polymer. For most of its optical applications, the azopolymer PAZO is deposited as thin films with a thickness ranging from several nanometers to several microns [ 7 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ].…”