Novel amino-acid-based polymer/multi-walled carbon nanotube bio-nanocomposites: highly water dispersible carbon nanotubes decorated with gold nanoparticles

Abstract

A well-reproducible and completely green route towards highly water dispersible multi-walled carbon nanotubes (MWNT) is achieved by a non-invasive, polymer wrapping technique, where the polymer is adsorbed on the MWNT's surface. Simply mixing an amino-acid-based polymer derivative, namely poly methacryloyl beta-alanine (PMBA) with purified MWNTs in distilled water resulted in the formation of PMBA-MWNT nanocomposite hybrids. Gold nanoparticles (AuNPs) were further anchored on the polymer-wrapped MWNTs, which were previously sonicated in distilled water, via the hydrogen bonding interaction between the carboxylic acid functional groups present in the polymer-modified MWNTs and the citrate-capped AuNPs. The surface morphologies and chemistries of the hybrids decorated with nanoparticles were characterized by transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. Additionally, the composites were also prepared by the in situ free radical polymerization of the monomer, methacryloyl beta-alanine (MBA), with MWNTs. Thus functionalized MWNTs were studied by thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM) and TEM. Both methods were effective in the nanotube functionalization and ensured good dispersion and high stability in water over three months. Due to the presence of the high densities of carboxylic acid functionalities on the surface of CNTs, various colloidal nanocrystals can be attached to MWNTs.

Size-tailored synthesis of gold nanoparticles and their facile deposition on AAO-templated carbon nanotubes via electrostatic self-assembly: Application to H2O2 detection

“…Among various nanocomposites, gold nanoparticles decorated carbon nanotubes (AuNPs/CNTs) have attracted a great deal of interest in diversified areas such as optical, chemical and biological sensing, electronic and catalytic applications [1][2][3][4][5][6][7][8][9][10] due to their combined outstanding properties and versatile syntheses. Based on the binding mode between AuNPs and CNTs, there have been three main approaches for the decoration of AuNPs on the surface of CNTs [11][12][13], including direct [14][15][16][17][18][19][20][21][22][23], covalent [24][25][26][27][28] and non-covalent [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] depositions. Nevertheless, some important drawbacks of the direct and the covalent attachments involving the ineffective size control of the former and the multistep reactions of the latter are still left to be addressed.…”

“…Up until the present, the wrapping of CNTs with ionic polymer followed by the assembling with oppositely charged AuNPs has been extensively exploited [29,[31][32][33][34][35][37][38][39][40]. However, it should be noted that the covering of CNTs with polymer layers may hinder the electron transfer between the component species.…”

Biodegradable Polymers Derived From Amino Acids

“…Microspheres loaded with diclofenac sodium salt, triclosan and clofazimine were prepared and sustained delivery of the hydrophilic diclofenac sodium salt occurred. Kumar et al reported a polymer wrapping technique, where the polymer is adsorbed on the surface of multi‐walled carbon nanotubes (MWCNT's) 63. Simply mixing an amino acid based polymer derivative, namely poly(methacryloyl β ‐alanine) (PMBA) with purified MWNTs in distilled water resulted in the formation of PMBA‐MWCNT nanocomposite hybrids.…”

Fabrication of Gold Nanoparticle/Multi Walled Carbon Nanotube Hybrids by <I>In Situ</I> Reaction in Water Using Poly(acryloyl <I>β</I>-alanine)

“…[17][18][19][20][21] Recently Kumar et al reported the functionalization of acid treated i.e., oxidized multi walled carbon nanotubes (MWCNTs) with the help of poly methacryloyl -alanine and attachment of ex situ formed gold nanoparticles (AuNPs) on MWCNTs. 22 Very low concentration (0.1 mM) of preformed AuNPs was used in the experiment and many AuNPs were found in the bulk aqueous phase, and thus the adsorption of AuNPs was not quantitative.…”