Effect of cross-linker density of P(NIPAM-co-AAc) microgels at solid surfaces on the swelling/shrinking behaviour and the Young’s modulus

Burmistrova, Anna; Richter, M.; Üzüm, Çağrı; Klitzing, Regine von

doi:10.1007/s00396-011-2383-2

Cited by 119 publications

(171 citation statements)

References 39 publications

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“…In contrast to the effect of cross linker [24], the amount of co-monomer has almost no influence on the hysteresis. Figure 5.…”

mentioning

confidence: 72%

“…as was previously described in detail [24]. All elasticity measurements were performed in liquid medium using an uncoated CSC 38 silicon cantilever (Micromash).…”

Section: Elasticity Measurements Of Microgelsmentioning

confidence: 99%

“…The indenting part of the SFM tips were assumed to be spherical and its exact radius of curvature R was extracted from scanning electron microscope (SEM) images. The tip-sample contact point and the contribution of the electrostatic interactions on the force curves were determined by fitting the force data in the indentation regime and extrapolating it to the non-contact regime as was explained previously [24]. The error bars, which are shown in the relevant graphs, come from the calculation for at least three particles.…”

Section: Elasticity Measurements Of Microgelsmentioning

confidence: 99%

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The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

et al. 2011

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Abstract:The swelling/deswelling behaviour of microgel particles in the bulk and at the surface was studied and correlated to their mechanical properties. We focused on two kinds of particles: pure PNIPAM and PNIPAM-co-AAc particles. It was shown that the two step volume phase transition found for PNIPAM-co-AAc particles in the bulk disappears after the adsorption at the surface and only a one step transition was identified. The transition temperature increased strongly with increasing the co-monomer content. The dependence of the Young's modulus of the adsorbed microgel particles on the temperature and the co-monomer content was discussed. The investigations were performed via DLS and SFM.

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“…In contrast to the effect of cross linker [24], the amount of co-monomer has almost no influence on the hysteresis. Figure 5.…”

mentioning

confidence: 72%

“…as was previously described in detail [24]. All elasticity measurements were performed in liquid medium using an uncoated CSC 38 silicon cantilever (Micromash).…”

Section: Elasticity Measurements Of Microgelsmentioning

confidence: 99%

Section: Elasticity Measurements Of Microgelsmentioning

confidence: 99%

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The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

et al. 2011

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“…Burmistrova et al showed by Atomic Force Microscope indentation measurements that the elastic modulus increases with increasing amounts of cross-linker. 32 The Au-NPs partially hinder the microgel collapse at the VPTT which leads to a slight increase in the microgel volume in comparison to the unloaded polymer particles. The dimensions of the p-NIPAM 0.25 particles obtained from TEM images (Fig.…”

Section: Discussionmentioning

confidence: 99%

Interaction of gold nanoparticles with thermoresponsive microgels: influence of the cross-linker density on optical properties

Gawlitza

Turner

Polzer

et al. 2013

Phys. Chem. Chem. Phys.

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The interaction of spherical gold nanoparticles (Au-NPs) with microgels composed of chemically crosslinked poly-(N-isopropylacrylamide) is reported. Simple mixing of the two components leads to adsorption of the gold particles onto the microgels. Different loading densities can be achieved by varying the ratio of gold particles to microgel particles. The adsorption of gold nanoparticles is analysed by TEM, UV-Vis absorption spectroscopy and SAXS. The influence of the microgel mesh size on the adsorption of gold nanoparticles is investigated by using microgels with three different cross-linker densities. The results suggest a strong relationship between the nanoparticle penetration depth and the cross-linker density. This, in turn, directly influences the optical properties of the colloids due to plasmon resonance coupling. In addition, information about the mesh size distribution of the microgels is obtained. For the first time the change in optical properties by varying cross-linker density and temperature is directly related to the formation of dimers of gold particles, proven by SAXS.

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“…For purely charge-dependent microgels, less is known, although FitzGerald et al investigated pH-dependent swelling of adsorbed poly(2-vinylpyridine) microgels using in situ tapping mode AFM, and again found a swelling transition similar to that for the corresponding dispersed microgel system. 48 Thus, although the presence of the surface generally affect microgel shape, notably causing microgel flattening to an extent depending on microgel T g , cross-linking density, and microgel-surface interactions, 44 volume transitions of surface-bound microgels seem not to be strongly affected by surface pinning or interfacial crowding effects, the latter at least at low to intermediate although somewhat thinner, in order to achieve thermally triggered insulin release. 6 From direct pulsatile and extended release studies, the films were found to be able to release bursts of insulin over many cycles, the magnitude of the release controlled by the film thickness.…”

Section: Discussionmentioning

confidence: 99%

Factors Affecting Peptide Interactions with Surface-Bound Microgels

et al. 2016

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Effects of electrostatics and peptide size on peptide interactions with surfacebound microgels were investigated with ellipsometry, confocal microscopy, and atomic force microscopy (AFM). Results show that binding of cationic poly-L-lysine (pLys) to anionic, covalently immobilized, poly(ethyl acrylate-co-methacrylic acid) microgels increased with increasing peptide net charge and microgel charge density. Furthermore, peptide release was facilitated by decreasing either microgel or peptide charge density. Analogously, increasing ionic strength facilitated peptide release for short peptides. As a result of peptide binding, the surface-bound microgels displayed pronounced deswelling and increased mechanical rigidity, the latter quantified by quantitative nanomechanical mapping. While short pLys was found to penetrate the entire microgel network and to result in almost complete charge neutralization, larger peptides were partially excluded from the microgel network, forming an outer peptide layer on the microgels. As a result of this difference, microgel flattening was more influenced by the lower Mw peptide than the higher. Peptide-induced deswelling was found to be lower for higher Mw pLys, the latter effect not observed for the corresponding microgels in the dispersed state. While the effects of electrostatics on peptide loading and release were similar to those observed for dispersed microgels, there were thus considerable effects of the underlying surface on peptide-induced microgel deswelling, which need to be considered in the design of surface-bound microgels as carriers of peptide loads, e.g., in drug delivery or in functionalized biomaterials.

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Effect of cross-linker density of P(NIPAM-co-AAc) microgels at solid surfaces on the swelling/shrinking behaviour and the Young’s modulus

Cited by 119 publications

References 39 publications

The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

The Effect of Co-Monomer Content on the Swelling/Shrinking and Mechanical Behaviour of Individually Adsorbed PNIPAM Microgel Particles

Interaction of gold nanoparticles with thermoresponsive microgels: influence of the cross-linker density on optical properties

Factors Affecting Peptide Interactions with Surface-Bound Microgels

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