Direct Observation of Internal Structures in Poly(<i>N</i>-isopropylacrylamide) Chemical Gels

Hirokawa, Yoshitsugu; Jinnai, Hiroshi; Nishikawa, Yukihiro; Okamoto, Takuya; Hashimoto, Takeji

doi:10.1021/ma990437v

Cited by 103 publications

(90 citation statements)

References 20 publications

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“…For visualizing its microstructure, a fluorescent probe (8-anilino-1-naphthalenesulphonic acid ammonium salt) that luminesces only in hydrophobic environments 38 was doped into a hydrogel prepared with IPAAm/TiNSs (10.0/0.4 wt%). At a temperature above LCST, the hydrogel with an opaque appearance, in confocal laser scanning microscopy (Supplementary Methods), indeed displayed a large number of submicron-sized tiny luminescent domains (Fig.…”

Section: Resultsmentioning

confidence: 99%

Photolatently modulable hydrogels using unilamellar titania nanosheets as photocatalytic crosslinkers

et al. 2013

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Hydrogels, postmodulable in controlled time and space domains, attract particular attention due to their potential in bio-related applications. Towards this goal, photolatently reactive hydrogels are very promising. Here we develop photolatently modulable hydrogels, composed of a polymer network accommodating photocatalytic titania nanosheets at every crosslinking point. As titania nanosheets can utilize gelling water as their source of radicals, its long-lasting photocatalysis makes the hydrogels readily modulable. Benefiting from the hydrogelation mechanism, the gel network is finely compartmentalized, leading to sharp thermoresponses. As demonstrated by photo-micropatterning, non-diffusible titania nanosheets at the crosslinking points enable pointwise modulations with an excellent spatial resolution. The photolatent nature also makes it possible to conjugate them with other hydrogels and polymers.

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Section: Resultsmentioning

confidence: 99%

Photolatently modulable hydrogels using unilamellar titania nanosheets as photocatalytic crosslinkers

et al. 2013

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“…This feature causes drastic turbidity change, many studies are carried out. However, so far, though they are mainly focused on the micrometer-scale structure and the elastic light scattering properties [24], and almost no investigations have been reported on the nano-structural relation between the above-mentioned two characteristic anomalies in the hydrogels.…”

Section: Transaction Of the Materials Research Society Of Japanmentioning

confidence: 99%

SAXS Studies of Heterogeneous NIPA/SA Gels

Hara

Sueyoshi

Sugiyama

et al. 2009

Trans. Mat. Res. Soc. Japan

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After brief reviews on the high sensitivity to water content and multivalent-ion adsorption of a peak in the homogeneous NIPA/SA gels' the small angle X-ray scattering (SAXS) profiles, the influence of the crosslinker concentration, which gives rise to the heterogeneity in the NIPA/SA gel, on the SAXS peak has been reported. It has been found that there is a considerable change in the location and intensity of the SAXS peak around a certain crosslinker concentration where the gels become opaque.

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“…In fact this coil-to-globule transition of poly(NIPAM) has been clearly seen on a nanometer scale using atomic force microscopy (AFM) [158]. Using laser scanning confocal microscopy (LSCM), the mesoscopic internal structures of network polymers, including those of poly(NIPAM), were shown to be composed of continuous two-domain structures with dense and sparse regions in the polymer network demonstrating "fixed concentration fluctuations" [159].…”

Section: Temperature-sensitive or Thermo-responsive Gelsmentioning

confidence: 99%

Smart polymeric gels: Redefining the limits of biomedical devices

Chaterji

Kwon

Park

2007

Progress in Polymer Science

559

364

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This review describes recent progresses in the development and applications of smart polymeric gels, especially in the context of biomedical devices. The review has been organized into three separate sections: defining the basis of smart properties in polymeric gels; describing representative stimuli to which these gels respond; and illustrating a sample application area, namely, microfluidics. One of the major limitations in the use of hydrogels in stimuli-responsive applications is the diffusion rate limited transduction of signals. This can be obviated by engineering interconnected pores in the polymer structure to form capillary networks in the matrix and by downscaling the size of hydrogels to significantly decrease diffusion paths. Reducing the lag time in the induction of smart responses can be highly useful in biomedical devices, such as sensors and actuators. This review also describes molecular imprinting techniques to fabricate hydrogels for specific molecular recognition of target analytes. Additionally, it describes the significant advances in bottom-up nanofabrication strategies, involving supramolecular chemistry. Learning to assemble supramolecular structures from nature has led to the rapid prototyping of functional supramolecular devices. In essence, the barriers in the current performance potential of biomedical devices can be lowered or removed by the rapid convergence of interdisciplinary technologies.

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Direct Observation of Internal Structures in Poly(N-isopropylacrylamide) Chemical Gels

Cited by 103 publications

References 20 publications

Photolatently modulable hydrogels using unilamellar titania nanosheets as photocatalytic crosslinkers

Photolatently modulable hydrogels using unilamellar titania nanosheets as photocatalytic crosslinkers

SAXS Studies of Heterogeneous NIPA/SA Gels

Smart polymeric gels: Redefining the limits of biomedical devices

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