Palladium-based micellar nanohybrids: preparation and nonlinear optical response

Abstract

In the present work the synthesis and physicochemical characterisation of a new class of Pd-containing micellar nanohybrid systems are presented. The new systems consist of metallic Pd nanoparticles and well-defined diblock copolymers, possessing carbazole and b-ketoester side-chain functionalities, namely poly[2-(N-carbazolyl) ethyl methacrylate]-block-poly[2-(acetoacetoxy) ethyl methacrylate] (CbzEMA x -b-AEMA y ). Block copolymer synthesis has been carried out by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerisation. The presence of the b-ketoester groups within these diblock copolymers enabled the complexation and stabilisation of the Pd nanoparticles in tetrahydrofuran. Visualisation of the Pd-containing micellar nanohybrids was realised by means of transmission electron microscopy (TEM), providing information on the metal nanoparticle sizes. The nonlinear optical response of these polymer-metal nanohybrid systems has been systematically studied both in solution and in thin films, using the Z-scan technique, employing 35 ps, visible (532 nm) and infrared (1064 nm) laser excitation. Discussion in regards to the spectral position of the surface plasmon resonance (SPR) of the Pd nanoparticles and its effect on the nonlinear optical response of the micellar systems has been carried out in terms of a two-photon process.

Structure-Defined 3D Nanocomposite Polymer Networks: Versatile Heterogeneous Catalytic Platforms in Organic Synthesis

“…A highly stable PVP−Pd colloidal nanohybrid solution was prepared in methanol by following a previously reported synthetic protocol . An indicative UV‐vis spectrum of the solution (Figure ) shows the presence of a broad absorption tail between 300–800 nm appearing only in the case of the PVP/Pd system, which is typical for Pd nanoparticle colloidal systems …”

“…[42] An indicative UV-vis spectrum of the solution (Figure 1) shows the presence of a broad absorption tail between 300-800 nm appearing only in the case of the PVP/Pd system, which is typical for Pd nanoparticle colloidal systems. [43] The fabrication of structurally-defined Pd-containing nanocomposite networks was realized in a single step upon mixing appropriate amounts of the well-defined polyDMAEMA homopolymer and the PVPÀPd nanohybrid colloidal solution in methanol in the presence of 1,2-bis(2-iodo-ethoxy)ethane (BIEE) ( Figure 2). The latter acts as a crosslinking agent owing to its ability to react selectively with two adjacent DMAEMA moieties that are present on the polyDMAEMA linear chains resulting in the formation of a stable network.…”

Nonlinear Optical Response of Noble Metal Nanoparticles

“…Though the SPR of transition metal nanoparticles is located in the ultraviolet range, the NLO response cannot be resonantly enhanced, but instead, it can be influenced by other nonlinear processes. Pd and Pt nanoparticles have also been found to exhibit interesting nonlinear optical properties such as two-photon or multiphoton processes [46][47][48][49], RSA [50] and SA [13,[51][52][53]. Correspondingly, Pt nanoparticles can be used in optical limiting [50,53,54] and mode locking [52,53].…”

Mesoporous-silica-coated palladium-nanocubes as recyclable nanocatalyst in C–C-coupling reaction – a green approach

“…Several studies were already presented in literature to delay that phenomenon using micelle-like-or core-shell-nanostructures as potential nanocatalytic systems. [14][15][16][17][18][19][20] However, these surfactants or shells are either potentially harmful for the environment or very step-inefficient to produce. Other approaches used the deposition of small NCs in a mesoporous support which offers a large active surface area.…”