Metal-Immobilized Micellar Aggregates of a Block Copolymer from a Mixed Solvent for a SERS-Active Sensing Substrate and Versatile Dip Catalysis

Abstract

Here, we have reported micellar aggregations of an amphiphilic block copolymer in mixed solvent and their subsequent use as a template for the fabrication of a very dense, tunable metal nanoparticle-decorated surface for SERS and flexible dip catalysis applications. A silver nanoparticle-immobilized layer on silicon substrates shows excellent SERS (surface-enhanced Raman scattering)-based sensing performance for model analyte rhodamine B up to 10 −6 M concentration with a well-defined calibration curve. Furthermore, a facile approach to the preparation of metal NPimmobilized BCP membranes as efficient dip catalyst for two model reactions (the reduction of nitrophenol and the Suzuki−Miyaura reaction of iodobenzene or 2,7diiodofluorene with phenyl boronic acid) is also demonstrated. The Ag NP-decorated film exhibits high efficiency and extensive reusability in a prototype reaction such as the reduction of nitrophenol by sodium borohydride with a very high turnover number, >126 (for a single use), whereas the Pd NPimmobilized film also has a high, ∼100%, reaction yield and extensive reusability and applicable for different aromatic systems. This work provides a new platform for the design and synthesis of a functionalizable, flexible, and highly mechanically stable dip catalyst which is highly demanded in the catalytic production of value-added chemicals and environmental applications such as wastewater treatment.

Advances in Surface-Enhanced Raman Scattering Sensors of Pollutants in Water Treatment

“…Here, the detection of pollutants such as pesticides, herbicides, and organic dyes for water treatment is addressed (see Table 1). We start with the detection of organic dyes [54][55][56][57][58][59][60], then those of pesticides [61][62][63][64][65][66], and finally those of herbicides [67,68].…”

“…The SERS substrate was achieved by copolymerizing the molecular imprinted polymer (MIP) on a defect-graphene layer with Ag nanoparticles, and they realized a LOD of 2.5 × 10 −15 M for detecting PNA in river water, owing to the presence of hotspots produced by the gaps between AgNPs [59]. To finish this part on the detection of organic dyes, Daripa et al carried out a SERS substrate composed of a block copolymer film (block copolymer polystyreneblock-poly(acrylic acid), called PS-b-PAA), which is decorated with silver nanoparticles [60] (see Figure 1a,b). A LOD of 10 −6 M for Rhodamine B detected in water was found (see Figure 1c), which is similar or higher than what has been demonstrated in the literature with this strategy based on a block copolymer.…”

“…A LOD of 10 −6 M for Rhodamine B detected in water was found (see Figure 1c), which is similar or higher than what has been demonstrated in the literature with this strategy based on a block copolymer. The enhancement of the Raman signal was due to the presence of hotspots generated by the coupling between Ag nanoparticles [60]. Regarding the detection of pesticides, Shi et al developed another interesting idea of a SERS substrate for the detection of the pesticide (4-Aminothiophenol: 4-ATP) in river water [62].…”

UV Cross-Linked Polymer Stabilized Gold Nanoparticles as a Reusable Dip-Catalyst for Aerobic Oxidation of Alcohols and Cross-Aldol Reactions

“…The AuNP-embedded membrane can directly be used as a dip-catalyst where the catalyst is simply separated from the reaction mixture by just taking out the membrane after the completion of the reaction and can be recycled several times without losing its catalytic activity significantly. One of the most important parameters for such dip-catalysis is the strong binding of AuNPs on the membrane surface to avoid a leaching problem. − As per the literature survey, there are few reports on AuNP-based dip-catalysis using different types of substrates like polymer membranes (dopamine, polyamide-12, and block copolymers), − cellulose, and jute stem . Using these Au-based dip catalytic systems, very few simple reactions like the reduction of 4-nitrophenol to 4-aminophenol, , nitroarene, and quinoline were carried out.…”

Polymer nanocomposite membranes and their application for flow catalysis and photocatalytic degradation of organic pollutants

“…The booming development of nanotechnology enables us to design and develop advance materials for a wide range of applications starting from energy storage, environmental protection to catalysis [1][2][3]. In the field of nanotechnology, development of new and novel polymer nanocomposite materials is a high priority area because of their immense potentials applications in all branches of science and technology [4][5][6][7][8][9][10][11]. Polymer nanocomposites are hybrid materials of polymer and nanomaterial having at least one dimension in between 1 to 100 nm, where polymers commonly serve as matrix and the nanomaterials with small quantity are dispersed within it [12].…”