Biomimic modification of graphene oxide

Abstract

5Surface modification of graphene oxide has attracted increasing attention in recent years. In this article, a green, facile and efficient method was developed to modify graphene oxide with polymers via combination of mussel inspired chemistry and Michael addition reaction. Graphite powder was first oxidated and exfoliated into single layer of slices through a modified Hummers method, then coated with polydopamine, which was formed via self polymerization of dopamine in alkaline solution. Next, the 10 intermediate (GO-PDA) was grafted by polyacrylic acid, which was synthesized via reversible additionfragmentation chain transfer polymerization, through Michael addition reaction. The resulting products were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, transmission electron microscopy and X-ray photoelectron spectrometry. The characterization results indicated the success of adhesion and graft of PDA and polyacrylic acid, respectively. The resulting products also 15 exihibited sensitivity to pH. Apart from the polymer demonstrated in this work, many other polymers may be also grafted onto graphene oxide through the strategy when different monomers were adopted. Furthermore, this strategy can be also extended to surface modification of many other materials for the versatility of mussel inspired chemistry. It is therefore recommended that the novel strategy developed in this work should be a general strategy for fabrication of various functional nanocomposites, which can 20 exihibit better performance for different applications.

Improving the drug delivery characteristics of graphene oxide based polymer nanocomposites through the “one-pot” synthetic approach of single-electron-transfer living radical polymerization

“…In our former report, a novel approach combines mussel inspired chemistry and free radical polymerization was carried out. [28] We demonstrated that GO can be functionalized with various polymers for different applications. [33] Nevertheless, most of these modification strategies are not easily to realize because immobilization of initiators and polymerization procedures are required under non-aqueous solvents.…”

“…[9][10][11][12][13][14][15][16][17] Among them, the GO based polymer nanocomposites should be the most important ones due to the combination advantages of both GO and polymers. [17][18][19][20][21][22][23][24][25][26][27][28][29] Previously, fabrication of GO based polymer nanocomposites through controlled living radical polymerization methods such as reversible addition fragmentation chain transfer (RAFT) polymerization, atom transfer radical polymerization (ATRP) and single-electrical transfer living radical polymerization (SET-LRP) has been developed. [29][30][31][32] These GO based polymer nanocomposites have demonstrated to be promising candidates for different applications.…”

Versatile Surface Modification Using Polydopamine and Related Polycatecholamines: Chemistry, Structure, and Applications

“…Polydopamine can be used as an intermediary surface material to allow attachment of other materials or chemical species without requiring prefunctionalization. This is because the contained quinone groups are electron deficient and are themselves reactive in Schiff base type couplings to amines as well as activating the aromatic ring to Michael addition reactions with nucleophilic groups such as amines, imidazoles, and thiols ( Figure ) . The reactivity of polydopamine surfaces toward these nucleophiles is dependent on the catechol/quinone equilibrium and consequently alkaline pH accelerates conjugation reactions .…”

“…In this instance, the p K a of the nucleophile is also relevant as it is deprotonated nucleophiles that react and so for neutral pH imidazole (p K a ≈ 6) reacts better than a primary amine (p K a ≈ 10), but this is reversed at higher pH . The coupling between nucleophiles and polydopamine surfaces have been used for the attachment of small molecules, synthetic polymers, biomolecules, and the construction of metal–organic frameworks …”

“…One way to achieve this is through the dispersal of graphene oxide into solution containing dopamine. Oxidative polymerization of the dopamine simultaneously reduces the graphene oxide and provides a coating ready for further modifications for versatile application in diverse fields including biosensors, energy storage, water purification, and biomedicine …”