Swelling, pH sensitivity, and mechanical properties of poly(acrylamide‐co‐sodium methacrylate) nanocomposite hydrogels impregnated with carboxyl‐functionalized carbon nanotubes

Abstract

A series of novel nanocomposite hydrogels were prepared by a cross‐linking copolymerization method. Structural and morphological characterizations of the nanocomposite hydrogels revealed that a good compatibility exists between poly(acrylamide‐co‐sodium methacrylate) [P(AM‐co‐SMA)] and carboxyl‐functionalized carbon nanotubes (MWNTs–COOH). The P(AM‐co‐SMA)/MWNTs–COOH nanocomposite hydrogels with a suitable MWNTs–COOH loading exhibited better swelling capability, higher pH sensitivity, good reversibility, and repeatability, and rapid response to external pH stimuli, compared with the P(AM‐co‐SMA). The compression mechanical tests revealed that the nanocomposite hydrogel displayed excellent compressive strengths and elastic mechanical properties, with higher ultimate compressive stress, and meanwhile still retain a good recoverable strain in the presence of MWNTs–COOH. These excellent properties may primarily be attributed to effectively dispersing of a suitable MWNTs–COOH loading into the matrix of the polymers and formation of additional hydrogen bonds. The nanocomposite hydrogels were expected to find applications in drug controlled release and issue engineering. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Self-healable, super tough graphene oxide–poly(acrylic acid) nanocomposite hydrogels facilitated by dual cross-linking effects through dynamic ionic interactions

“…Therefore, increasing the content of the GO nanosheets results in the increase of the cross-linking density. At a moderate content, however, the GO nanosheets can be uniformly dispersed in the PAA matrix, and more PAA chains are enriched on the GO 20 surfaces through cross-linking, leading to a robust and flexible network structure translating into outstanding toughness and stretchability. The PAA concentration is also an important factor, since the variation in the water content is found to significantly influence 25 the elastic modulus, tensile strength and fracture energy of the GO/PAA nanocomposite hydrogels ( Fig.…”

“…3e). Note that the healed sample, after having been cut off and treated at 45 o C for 20 48 h, can be stretched over 20 times (Fig. 3e and Video 3 †, ESI).…”

“…Recently we have proposed a novel concept to prepare various 20 super tough and highly stretchable nanocomposite hydrogels by creating dual cross-linking effects within the 3-dimensional network structure, [14][15][16][17] i.e., "single network, dual cross-linking". 15 In those cases, silica nanoparticles with polymer brush serve as analogous cross-linking points through covalent interactions, 25 while the polymer chains are physically linked to form reversible (dynamic) cross-linking points.…”

Transparent h- BN/polyacrylamide nanocomposite hydrogels with enhanced mechanical properties

“…However, most of the existing natural and synthetic hydrogels have poor mechanical properties, which unfortunately limit their applications in many fields where tough and flexible hydrogels are necessary. In this sense, a surge of research has been reported on the development of nanocomposite hydrogels reinforced with various nanofillers, including clay nanosheets [16], silica nanoparticles [6,9,17], graphene oxide (GO) nanosheets [7,[18][19][20][21][22] and carbon nanotubes [23]. Recently, we have prepared a high-strength GO/PAA nanocomposite hydrogels composed of a single network with dual crosslinking points through dynamic ionic interactions [7].…”

Fabrication and characterization of a nanocomposite hydrogel for combined photocatalytic degradation of a mixture of malachite green and fast green dye

“…These days, number of materials has been used such as carbon nanotubes, graphene oxide, carbon dots, metal oxides and ceramics, etc. so as to make novel nanocomposite hydrogels having improved mechanical properties [22][23][24][25].…”