Kinetic aspects, rheological properties and mechanoelectrical effects of hydrogels composed of polyacrylamide and polystyrene nanoparticles

Abstract

Snake-cage gels were prepared using monodisperse polystyrene (PS) nano-sized particles (R = 200 nm) in place of the more commonly used linear polymer. The kinetics of the formation of the complementary polyacrylamide (PAM) hydrogel was studied alone or in the presence of the PS nanoparticles by 1 H-NMR. Without PS, the reactivity ratios of the acrylamide (Am) and the cross-linking agent N,N9-methylene-bisacrylamide (BisAm) were computed using the initial kinetics of PAM gel at high cross-linker concentration (r A = 0.52 and r B = 5.2 for Am and BisAm, respectively). In the presence of PS, during the formation of nanoparticle composite (NPC) gels, there was a decrease in the conversion rate with an increasing fraction of PS nanoparticles. This could be explained by steric effects, which induce an increase of the elastic modulus of the matrix with the increasing fraction of PS nanoparticles. There was a considerable increase in the rheological properties of the NPC gels (i.e. tensile modulus), which was more pronounced at higher fractions of nanoparticles. We used particular mechanical properties to develop a stimulus-responsive (''smart'') material, i.e. a mechanoelectrical effect, which may be used in the development of soft and wet tactile-sensing devices.

Nanoparticle–Hydrogel Composites: Concept, Design, and Applications of These Promising, Multi‐Functional Materials

“…[ 66 ] www.MaterialsViews.com www.advancedscience.com ( Figure 12 ). [ 89 ] Polypyrrole (PPy) is a semi-conducting conjugated polymer used in organicbased optoelectronic devices. Luo et al developed an agarose/ alginate double network hydrogel incorporating PPy NPs for use as an infrared responsive releasing system, much like those employing reduced graphene oxide NPs.…”

“…Thevenot et al developed hybrid materials with differing elastic moduli by using alternating layers of PAAm hydrogel composites with and without PS‐NP fillers. Physical deformation of this bi‐layer gel produced an electrical potential, useful in developing soft tactile‐sensing devices ( Figure ) . Polypyrrole (PPy) is a semi‐conducting conjugated polymer used in organic‐based optoelectronic devices.…”

Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity

“…The instantaneous number-average sequence length of NaSS monomer, <N> NaSS, and MPTC monomer, <N> MPTC, can be expressed with the total monomers conversion point p according to the Mayo-Lewis theory 39 . The results are shown in Supplementary Fig.1d.…”

Hydrogel Retaining Toxin‐Absorbing Nanosponges for Local Treatment of Methicillin‐Resistant Staphylococcus aureus Infection

“…[16] We observed slightly higher values of G ′ and G ″ at high frequencies for the NS-gel formulation as compared to those of the empty hydrogel (without nanosponges), which is likely due to adhesive interactions between the nanosponges and the acrylamide polymer matrix. [15, 31] Nevertheless, G′ and G″ values measured from NS-gel were generally close to those measured from the empty hydrogel, suggesting a negligible effect of the loaded nanosponges on the gel’s rheological characteristics. We then freeze-dried the NS-gel and observed its structure under scanning electron microscope (SEM).…”