Dip in colorimetric fluoride sensing by a chemically engineered polymeric cellulose/bPEI conjugate in the solid state

Abstract

The cross-linking, via amide bond formation, of TEMPO-oxidized cellulose nanofibers with branched-polyethyleneimine functionalized with pNO2-phenyl urea units generates a novel polymeric conjugate material, with a sponge-like morphology, which can be successfully used for the heterogeneous sensing of fluoride anions in DMSO solution

Naked‐Eye Heterogeneous Sensing of Fluoride Ions by Co‐Polymeric Nanosponge Systems Comprising Aromatic‐Imide‐Functionalized Nanocellulose and Branched Polyethyleneimine

“…Different degrees of bPEI functionalization can be obtained by varying the equivalents of anhydride derivatives 1–3 (Scheme ) with respect to the amount of primary amines present on the reacting bPEI (estimated by previous studies to be ca. 7.43 mmol⋅g −1 ) . It is expected that the sensor capability of the final material depends on the relative amount of sensor units.…”

“…In this case, the 0.20 equivalents of reactant were used with two different reaction time (30 minutes and 1 hour). The synthesis of the sponge‐like materials was performed similarly to as previously reported . Briefly, a solution of functionalized and non‐functionalized bPEI in different percentage was added to a fine suspension of TOCNF.…”

“…Indeed, functionalized materials S1 and S2 are capable to selectively recognize the presence of fluoride by the naked‐eye over chloride, phosphate and acetate, common interfering species, when dipped into DMSO solution. Effective sensing of fluoride can be obtained up to about 0.05 M, thus lowering the naked‐eye detection concentration threshold of about an order of magnitude compared to previous works . Moreover, it is demonstrated that sensing can also be achieved by using an S3 sample material having only 0.02 % w/w of chromophore units per gram of material.…”

“…Effective sensing of fluoride can be obtained up to about 0.05 M, thus lowering the naked-eye detection concentration threshold of about an order of magnitude compared to previous works. [16] Moreover, it is demonstrated that sensing can also be achieved by using an S3 sample material having only 0.02 % w/w of chromophore units per gram of material. Finally, this work confirms the high versatility of this class of functionalized cellulose-based materials.…”

Surface-Functionalization of Nanostructured Cellulose Aerogels by Solid State Eumelanin Coating

“…21 Moreover, we have extended this protocol to the preparation of novel polymeric conjugate materials, with a porous structure, which were successfully used for the heterogeneous sensing of fluoride anions in DMSO solution. 22 Alternative approaches involve use of CNF-aerogels as templates for either inorganic or organic coatings. 23−27 A highly attractive, yet still apparently unexplored entry to CNF functionalization would be based on the exploitation of the unique physicochemical properties of eumelanins, 28−32 the antioxidant and photoprotective pigments of human skin and eyes.…”