Temperature-sensitive aqueous microgels

Pelton, Robert

doi:10.1016/s0001-8686(99)00023-8

Cited by 1,770 publications

(1,746 citation statements)

References 84 publications

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“…24 These particles were crosslinked with BA. 18 Styrene (4.50 g), BA (0.15 g), and NIPAM (4.50 g for S/N 1 and 0.56 g for S/N 8) were added into 500 mL of deionized water in a 1000 mL three-neck reactor fitted with nitrogen bubbling inlet and outlet, equipped with a reflux condenser and a mechanical stir. After stirring the solution for 40 min at 70 C under nitrogen bubbling, the polymerization was initiated by adding potassium persulfate (K 2 S 2 O 8 , KPS, 0.15 g) dissolved in 10 mL of deionized water.…”

Section: Preparation Of Particlesmentioning

confidence: 99%

Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles

Harbottle

Pensini

et al. 2015

Langmuir

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Two distinct uniform hybrid particles, with similar hydrodynamic diameters and comparable zeta potentials, were prepared by copolymerizing N-isopropyl acrylamide (NIPAM) and styrene.These particles differed in their styrene to NIPAM (S/N) ratios of 1 and 8, and were referred to as S/N 1 and S/N 8. Particle S/N 1 exhibited typical behavior of soft particles, i.e., the particles shrank in bulk aqueous solutions when the temperature was increased. As a result, S/N 1 particles were interfacially active. In contrast, particle S/N 8 appeared to be rigid in response to temperature changes. In this case, the particles showed negligible interfacial activity. Interfacial shear rheology tests revealed the increased rigidity of the particle-stabilized film formed at the heptane-water interface by S/N 1 than S/N 8 particles. As a result, S/N 1 particles were shown to be better emulsion stabilizers and emulsify a larger amount of heptane compared to S/N 8 particles. The current investigation confirmed a better performance of emulsion stabilization by soft particles (S/N 1) than by rigid particles (S/N 8), reinforcing the importance of controlling softness or deformability of particles for the purpose of stabilizing emulsions.

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Section: Preparation Of Particlesmentioning

confidence: 99%

Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles

Harbottle

Pensini

et al. 2015

Langmuir

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“…Soft colloids, such as foams, emulsions and particles made from poly(Nisopropyl acrylamide) microgels (NIPA particles) [105,106], can be used to study densities above the jamming transition. In aqueous solution, NIPA colloids swell substantially as the temperature is reduced only slightly.…”

Section: Colloidsmentioning

confidence: 99%

The jamming scenario—an introduction and outlook

Liu

Nagel

Saarloos

et al. 2011

Dynamical Heterogeneities in Glasses, Colloids, and Granular Media

119

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Abstract. The jamming scenario of disordered media, formulated about 10 years ago, has in recent years been advanced by analyzing model systems of granular media. This has led to various new concepts that are increasingly being explored in in a variety of systems. This chapter contains an introductory review of these recent developments and provides an outlook on their applicability to different physical systems and on future directions. The first part of the paper is devoted to an overview of the findings for model systems of frictionless spheres, focussing on the excess of low-frequency modes as the jamming point is approached. Particular attention is paid to a discussion of the cross-over frequency and length scales that govern this approach. We then discuss the effects of particle asphericity and static friction, the applicability to bubble models for wet foams in which the friction is dynamic, the dynamical arrest in colloids, and the implications for molecular glasses.

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“…Previous workers have reported on the fabrication of temperature-responsive hydrogel valves [36][37][38][39]. For example, Yu et al prepared monolithic plugs of hydrogel by photo-initiated polymerization within the conduits of a microfluidic device and demonstrated over 120 openclose cycles [37].…”

Section: Introductionmentioning

confidence: 99%

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

Wang

Chen

Mauk

et al. 2005

Biomed Microdevices

142

107

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An easy to fabricate, thermally-actuated, self-regulated hydrogel valve for flow control in pneumatically driven, microfluidic systems is described. This microvalve takes advantage of the properties of the hydrogel, poly(Nisopropylacrylamide), as well as the aqueous fluid itself to realize flow control. The valve was designed for use in a diagnostic system fabricated with polycarbonate and aimed at the detection of pathogens in oral fluids at the location of the sample collection. The paper describes the construction and characterization of the hydrogel valves and their application for flow control, sample and reagent metering, sample distribution into multiple analysis paths, and the sealing of a polymerase chain reaction (PCR) reactor to suppress bubble formation. The hydrogel-based flow control is electronically addressable, does not require any moving parts, introduces minimal dead volume, is leakage and contaminant free, and is biocompatible. KeywordsMicrovalve, microfluidics, hydrogel, lab-on-a-chip, metering, distribution, PCR Wang, J., Chen, Z., Mauk, M., Hong, K-S, Li, M., Yang, S., and Bau, H., H Wang, J., Chen, Z., Mauk, M., Hong, K-S, Li, M., Yang, S., and Bau, H., H., 2005, Self-Actuated, ThermoResponsive Hydrogel Valves for Lab on a Chip, Biomedical Microdevices 7 (4), 313-322.., 2005, Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip, Biomedical Microdevices 7 (4), 313-322. ABSTRACTAn easy to fabricate, thermally-actuated, self-regulated hydrogel valve for flow control in pneumatically driven, microfluidic systems is described. This microvalve takes advantage of the properties of the hydrogel, poly(N-isopropylacrylamide), as well as the aqueous fluid itself to realize flow control. The valve was designed for use in a diagnostic system fabricated with polycarbonate and aimed at the detection of pathogens in oral fluids at the location of the sample collection. The paper describes the construction and characterization of the hydrogel valves and their application for flow control, sample and reagent metering, sample distribution into multiple analysis paths, and the sealing of a polymerase chain reaction (PCR) reactor to suppress bubble formation. The hydrogel-based flow control is electronically addressable, does not require any moving parts, introduces minimal dead volume, is leakage and contaminant free, and is biocompatible.

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Temperature-sensitive aqueous microgels

Cited by 1,770 publications

References 84 publications

Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles

Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles

The jamming scenario—an introduction and outlook

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

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