Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy

Tang, Shijun; Hu, Zhibing; Cheng, Zhengdong; Wu, Jianzhong

doi:10.1021/la049203h

Cited by 57 publications

(69 citation statements)

References 43 publications

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“…Recent work has shown that thermosensitive suspensions are indeed excellent model systems for the study of colloidal crystals. 11,39,40 Then we demonstrate that flow curves up to effective volume fractions of 0.63 can be obtained. These data can then be used for a comparison with the theory of Fuchs and Cates, 37 and Fuchs.…”

Section: Gelsmentioning

confidence: 72%

Thermosensitive core-shell particles as model systems for studying the flow behavior of concentrated colloidal dispersions

Crassous

Siebenbürger

Ballauff

et al. 2006

The Journal of Chemical Physics

106

149

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We report on a comprehensive investigation of the flow behavior of colloidal thermosensitive core-shell particles at high densities. The particles consist of a solid core of poly͑styrene͒ onto which a network of cross-linked poly͑N-isopropylacrylamide͒ is affixed. Immersed in water the shell of these particles will swell if the temperature is low. Raising the temperature above 32°C leads to a volume transition within this shell which leads to a marked shrinking of the shell. The particles have well-defined core-shell structure and a narrow size distribution. The remaining electrostatic interactions due to a small number of charges affixed to the core particles can be screened by adding 0.05M KCl to the suspensions. Below the lower critical solution temperature at 32°C the particles are purely repulsive. Above this transition, a thermoreversible coagulation takes place. Lowering the temperature again leads to full dissociation of the aggregates formed by this process. The particles crystallize for effective volume fractions between 0.48 and 0.55. The crystallites can be molten by shear in order to reach a fluid sample again. The reduced shear stress measured in this metastable disordered state was found to be a unique function of the shear rate and the effective volume fraction. These reduced flow curves thus obtained can be described quantitatively by the theory of Fuchs and Cates ͓Phys. Rev. Lett. 89, 248304 ͑2002͔͒ which is based on the mode-coupling theory of the glass transition.

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Section: Gelsmentioning

confidence: 72%

Thermosensitive core-shell particles as model systems for studying the flow behavior of concentrated colloidal dispersions

Crassous

Siebenbürger

Ballauff

et al. 2006

The Journal of Chemical Physics

106

149

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“…(Scheme 1B)S ince the crystalline structure of microgel CCs is fragile and can be easily destroyed by heating or shearing, [22] it was first stabilized by forming ahydrogel matrix surrounding the microgel spheres, as shown in Scheme 1A. [23][24][25] As an example we synthesized aP NIPAM microgel CC doped with 10 %P (NIPAM-AAc) microgel.…”

Section: Methodsmentioning

confidence: 99%

Photonic Crystals with a Reversibly Inducible and Erasable Defect State Using External Stimuli

et al. 2015

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The controlled introduction of artificial extrinsic defects is critical to achieve the functions of photonic crystals. Smart defects capable of responding to external stimuli lead to more advanced applications.H ere we report am icrogel colloidal crystal with ad efect state whichc ould be induced and erased reversibly by external stimuli. The crystal was assembled from PNIPAM microgel and P(NIPAM-AAc) microgel of the same size. The resulting doped crystal does not exhibit adefect state in its stop band because of the similar optical properties of the dopant and the host. By increasing the pH value,however,the dopant P(NIPAM-AAc) spheres swell to alarger size and turn into real defects in the crystal, resulting in the appearance of defect state.Adjusting the pH value back restores the sizeo ft he dopant spheres,a nd thus erases the defect state.T emperature,as econd external stimulus,c ould also be used to induce and erase defect states of the crystal.

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“…Thus, very fast density quenches and, furthermore, very high densities that require a compression or interpenetration of the particles can be studied. Moreover, a change from the compressed to the swollen state of the particles allows us to study the transition from HS-like to soft particles in a single experimental system [144,145]. With UV-visible spectroscopy measurements the crystallization kinetics of aqueous suspensions of PNIPAM particles was followed at different temperatures corresponding to volume fractions 0.51 < φ < 0.56 [145].…”

Section: Soft Particlesmentioning

confidence: 99%

“…Moreover, a change from the compressed to the swollen state of the particles allows us to study the transition from HS-like to soft particles in a single experimental system [144,145]. With UV-visible spectroscopy measurements the crystallization kinetics of aqueous suspensions of PNIPAM particles was followed at different temperatures corresponding to volume fractions 0.51 < φ < 0.56 [145]. In the swollen state, the kinetics of the crystallinity, the number of crystals and the average size of the crystals was found to be close to results obtained with HS in micro-gravity [64].…”

Section: Soft Particlesmentioning

confidence: 99%

Crystallization in three- and two-dimensional colloidal suspensions

Gasser

2009

J. Phys.: Condens. Matter

236

242

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Despite progress in the understanding of crystal nucleation and crystal growth since the first theories for nucleation were developed, an exact quantitative prediction of the nucleation rates in most systems has remained an unsolved problem. Colloidal suspensions show a phase behavior that is analogous to atomic or molecular systems and serve accordingly as ideal model systems for studying crystal nucleation with an accuracy and depth on a microscopic scale that is hard to reach for atomic or molecular systems. Due to the mesoscopic size of colloidal particles they can be studied in detail on the single-particle level and their dynamics is strongly slowed down in comparison with atomic or molecular systems, such that the formation of a crystal nucleus can be followed in detail. In this review, recent progress in the study of homogeneous and heterogeneous crystal nucleation in colloids and the controlled growth of crystalline colloidal structures is reviewed. All this work has resulted in unprecedented insights into the early stage of nucleation and it is also relevant for a deeper understanding of soft matter materials in general as well as for possible applications based on colloidal suspensions.

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Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy

Cited by 57 publications

References 43 publications

Thermosensitive core-shell particles as model systems for studying the flow behavior of concentrated colloidal dispersions

Thermosensitive core-shell particles as model systems for studying the flow behavior of concentrated colloidal dispersions

Photonic Crystals with a Reversibly Inducible and Erasable Defect State Using External Stimuli

Crystallization in three- and two-dimensional colloidal suspensions

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