Contrast variation SANS measurement of shell monomer density profiles of smart core–shell microgels

Cors, Marian; Wiehemeier, Lars; Wrede, Oliver; Feoktystov, Artem; Cousin, Fabrice; Hellweg, Thomas; Oberdisse, Julian

doi:10.1039/c9sm02036e

Cited by 19 publications

(23 citation statements)

References 62 publications

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“…The swollen pNIPAM shell cannot be identified. This may result from an interpenetration into the deswollen p(NIPAM-co-DAAM) network in combination with the small thickness [53][54][55].…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure of temperature-sensitive nanocapsules

et al. 2020

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The transport and systematic release of functional agents at specific areas are key challenges in various application fields. These make the development of micro-and nanocapsules, which allow for uptake, storage, and triggered release, of high interest. Hollow thermoresponsive microgels, cross-linked polymer networks with a solvent-filled cavity in their center, are promising candidates as triggerable nanocapsules, as they can adapt their size and shape to the environment. Their shell permeability can be controlled by temperature, while the cavity can serve as a storage place for guest species. Here, we present the synthesis and structural characterization of temperature-responsive microgels, which are deswollen at room temperature and swell upon moderate cooling, to facilitate potential encapsulation experiments. We present microgels made from poly(N-isopropylacrylamide-co-diacetone acrylamide), p(NIPAM-co-DAAM), possessing a volume phase transition temperature below room temperature. Their colloidal stability in the deswollen state can be enhanced by adding a swollen polymer shell made of poly(N-isopropylacrylamide), pNIPAM, as periphery. The synthesis of hollow double-shell microgels comprising a cavity surrounded by an inner p(NIPAM-co-DAAM) shell and an outer pNIPAM shell is established. The inner network enables the control of the shell permeability: the network is deswollen at room temperature and swells upon moderate cooling. The outer network guarantees for steric stability at room temperature. Light scattering techniques are employed for the characterization of the microgels. Form factor analysis reveals that the cavity of the nanocapsules persists at all swelling states, making it an ideal site for the storage of guest species.

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“…The swollen pNIPAM shell cannot be identified. This may result from an interpenetration into the deswollen p(NIPAM-co-DAAM) network in combination with the small thickness [53][54][55].…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure of temperature-sensitive nanocapsules

et al. 2020

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“…Our approach combined several measurements: at first, a pure p(NIPMAM) core ("core-only"), onto which either deuterated or hydrogenated p(NNPAM) shells have been grown. It is stressed that all cores are the same in our studies [57,59,61,89], i.e. the second synthesis step of the shell has been performed with pre-existing cores, enabling thus direct comparisons.…”

Section: Form-free Density Profiles Of Spherically Symmetric Microstrmentioning

confidence: 99%

“…The resulting SANS curves have been analysed by applying our form-free multi-shell RMC procedure to the data, and the result is shown in Fig. 5b [89].…”

Section: Form-free Density Profiles Of Spherically Symmetric Microstrmentioning

confidence: 99%

“…Hence, the particles have the following structure: AuAg@p(NIPAM-co-allylamine)@Ag. The distribution of [89] with permission from the The Royal Society of Chemistry the Ag particles inside the polymer shell is described by the term "satellites" by the authors.…”

Section: Applications Of Core-shell Microgels In Catalysismentioning

confidence: 99%

“…(b) Density profile of the D7-p(NNPAM) shell monomers of same system with contrast matched core (H2O/D2O = 77v%/23v%).Fig. 5bwas reproduced from[89] with permission from the The Royal Society of Chemistry.…”

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confidence: 99%

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Recent advances in stimuli-responsive core-shell microgel particles: synthesis, characterisation, and applications

Oberdisse

Hellweg

2020

Colloid Polym Sci

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Inspired by the path followed by Matthias Ballauff over the past 20 years, the development of thermosensitive core-shell microgel structures is reviewed. Different chemical structures, from hard nanoparticle cores to double stimuli-responsive microgels have been devised and successfully implemented by many different groups. Some of the rich variety of these systems is presented, as well as some recent progress in structural analysis of such microstructures by small-angle scattering of neutrons or X-rays, including modelling approaches. In the last part, again following early work by the group of Matthias Ballauff, applications with particular emphasis on incorporation of catalytic nanoparticles inside core-shell structures-stabilising the nanoparticles and granting external control over activity-will be discussed, as well as core-shell microgels at interfaces.

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Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

Oberdisse

Hellweg

2022

Smart Stimuli‐Responsive Polymers, Films, and Gels

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Meanwhile since more than three decades smart micro-and nanogels are studied and the number of publications in this area of research is steadily growing. This year to date (May 2021) already more than 400 articles were published on this topic. In the study of such colloidal gels the most important techniques besides microscopy are scattering techniques.In the present chapter an introduction to these non-destructive techniques and their application to smart micro-and nanogels will be given, and besides some fundamental works on this topic the most recent studies in this context will be discussed. We put a focus on multi-compartment and multi-1 stimuli responsive microgels and review time-resolved small-angle scattering experiments. In addition one section is devoted to the study of crowded microgel systems.

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Contrast variation SANS measurement of shell monomer density profiles of smart core–shell microgels

Abstract: The radial density profile of deuterated poly(N,n-propyl acrylamide) shell monomers within core–shell microgels has been studied by small-angle neutron scattering in order to shed light on the origin of their linear thermally-induced swelling.

Cited by 19 publications

References 62 publications

Synthesis and structure of temperature-sensitive nanocapsules

Synthesis and structure of temperature-sensitive nanocapsules

Recent advances in stimuli-responsive core-shell microgel particles: synthesis, characterisation, and applications

Structure and Properties of Smart Micro‐ and Nanogels Determined by (Neutron) Scattering Methods

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