Synthesis and Characterization of Fluorescent PVA/PVAc-Rodhamine Microspheres

Abstract

Fluorescent polymeric microspheres are used in a wide range of biomedical and technological applications, including blood flow determination, screening, flow visualization, flow tracing, medical imaging, fluorescence microscopy and flow cytometry among others. Rhodamine 6G (R6G) is a lipophilic cationic dye, which is among the most stable organic fluorophores, and with a high quantum yield in fluorescence (absorption and emission) in the visible range (500-600 nm). It is mainly applied in laser technology, and also in fluorescent bioimage. In this work we present an efficient synthesis route to obtain Polyvinyl Alcohol/Polyvinyl Acetate (PVA/PVAc) spherical microparticles containing Rhodamine 6G in a concentration sufficient to exploit their fluorescent properties. The synthesis method comprises the suspension polymerization of Vinyl acetate (VAc) monomer in the presence of Rhodamine, followed by saponification. Microspheres loaded with 1.9% w / w of Rhodamine 6G were obtained. They presented good sphericity and a size distribution in the range of 20 to 1550 microns. The fluorescence intensity of the microspheres was measured by UV-Vis and fluorescence spectroscopy, and detected using an image-based experimental setup, respectively. The results obtained with these methodologies showed that our microspheres exhibit fluorescence and that they are quite detectable in water flows. However, the response of UV-Visible fluorescence and absorbance was affected by the presence of the PVA / PVAc polymer matrix.

Preparation of the Heterogeneous Saponified Poly(Vinyl Alcohol)/Poly(Methyl Methacrylate–Methallyl Alcohol) Blend Film

“…T g of the untreated PVAc/PMMA agrees well with the other reported results [ 57 , 58 ]. Similar results are obtained in the case of the other blend films (PVAc/PMMA 5:5), which demonstrate a higher thermal property (T g ) after the saponification treatment, which could be due to the conversion of PVAc/PMMA into PVA/P(MMA-MAA) blend films because PVA possesses a higher thermal property (Tg) than PVAc [ 59 ]. However, saponified PVAc/PMMA 7:3 film showed a lower thermal property (T g ) than the unsaponified PVAc/PMMA 7:3 film, which could be due to a weak PVA and P(MMA-MAA) interaction after saponification, as higher conversion of PMMA to P(MMA-MAA) occurred at this blend ratio after saponification than at other ratios (9:1 and 5:5) ( Figure 2 ).…”

Porous Sulfonated PVA Microspheres for Controlled Molecules Delivery: A Methylene Blue Study

“…In addition, a highly porous surface can be distinguished in the detail of Figure 5A. Previously we have observed porosity in PVA-PVAc microspheres obtained by the free radical polymerization method, followed by saponification [42]. This result is related to the addition of organic solvents in the reaction medium during the polymerization stage.…”

“…This result is related to the addition of organic solvents in the reaction medium during the polymerization stage. The removal of these solvents at the end of the reaction generates porosity in the final material [13,42,43]. An attempt was made to measure the BET surface area of the microspheres by performing a lyophilization pretreatment.…”

“…M. G. Verón et alJournal of Materials and Applications 2021;10(1):[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] …”

Enhanced Dye Adsorption of Mixed‐Matrix Membrane by Covalent Incorporation of Metal‐Organic Framework with Poly(styrene‐alt‐maleic anhydride)

“…The PXRD pattern of the pure PVA has two diffraction peaks in the range between 2-theta values of 10-30°d ue to semi-crystalline structure of PVA. [41] Therefore, two new reflections between 2-theta values of 10-30°in the PXRD patterns are attributed to the shifted peaks of PVA. The PXRD results illustrate the formation of MMM did not damage the crystal structure of MOFs.…”