Color-Tunable Etalons Assembled from Poly (N-Isopropylacrylamide) Based Microgels

Stimuli responsive surface structures attract increasing attention due to a large variety of envisioned applications. The controlled organization of poly(N-isopropyl acrylamid), PNIPAM microgel particles at solid surfaces inspired numerous research activities. In this review article, we briefly discuss the swelling/deswelling properties of adsorbed microgel particles in comparison to the behavior in the bulk phase. The presence of the solid interface highly influences and changes their behavior with respect to the properties in solution. Furthermore, the confinement on a solid substrate allows the direct and in-situ investigation of the mechanical properties of the microgel particles. Additionally, we briefly review the research on microgel particles at liquid interfaces. At these interfaces new interesting effects occur. Moreover, we discuss some interesting work on potential applications. In this context, microgel particles are often used as an active component for responsive coatings of various functionality envisioning applications, e.g. in medicine, biotechnology, and nanooptics.Zusammenfassung: Responsive Oberflächenmaterialien finden aufgrund der damit verbundenen potentiellen technischen Anwendungsmöglichkeiten große Beachtung in der aktuellen Forschung. Die Möglichkeit, kolloidale Gelpartikel aus poly(N-Isopropylacrylamid), PNIPAM an festen Oberflächen kontrolliert anzuordnen, inspirierte vielfältige Forschungsakivitäten. In diesem Übersichtsartikel diskutieren wir das Quellverhalten adsorbierter Mikrogelpartikel im Vergleich zu

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“…Moreover, the chosen preparation technique has an influence on the homogeneity of the optical performance, e.g. [44,48,94,101,102,113].…”

Section: Optical Devices Sensors and Switchesmentioning

confidence: 99%

Responsive Microgels at Surfaces and Interfaces

Wellert

Richter

Hellweg

et al. 2014

Zeitschrift Für Physikalische Chemie

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“…Specically, pNIPAm-based microgels transition from a swollen (large diameter) to a collapsed (small diameter) state at elevated temperature. 4,[23][24][25][26][27][28][29][30][31][32] The structure of this device can be seen in Fig. PNIPAmbased microgels can also be made responsive to other stimuli, in addition to temperature.…”

Section: Introductionmentioning

confidence: 99%

Controlled release kinetics from a surface modified microgel-based reservoir device

et al. 2015

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A device constructed by sandwiching a thin film of poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAmco-AAc) microgels between two thin layers of Au (all on a glass support) was used as a novel platform for controlled release of small molecules (drugs). In this submission, the model drug tris (4-(dimenthylamino) phenyl)methylium chloride (Crystal Violet, CV) was loaded into the microgel layer of the device by electrostatic interaction of its positive charge with the negative charges on the deprotonated AAc groups on the microgels at pH > 6.5. The upper Au layer of this device was coated with SiO 2 generated by hydrolysis of tetraethyl orthosilicate (TEOS) catalyzed by ammonia at room temperature. Upon exposing the CV loaded devices to pH 3 solutions, the microgel AAc groups were neutralized, and the CV released. The release rate of the CV could be controlled by the thickness of the SiO 2 layer coating the Au layer. Specifically, devices with thick silica layers slow the release rate and thin layers allow for faster release. This device represents an easily fabricated device for controlled and triggered release from a thin film with easily controlled release kinetics.

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“…Therefore, smart hydrogels have been designed to sense these stimuli based on gel volume change. A commonly cited example is the poly N-isopropylacrylamide (pNIPAm) hydrogel that shows temperaturedependent volume change [18,19]. At low temperature, the water-polymer interaction is strong and the gel is highly swelled.…”

Section: Stimuli Responsive Hydrogelsmentioning

confidence: 99%