Mapping Polymer Phase Diagram in Nanoliter Droplets

Shi, Feng; Han, Zuoyan; Li, Junfang; Zheng, Bo; Wu, Chi

doi:10.1021/ma102917u

Cited by 6 publications

(14 citation statements)

References 24 publications

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“…T dem obtained with the 0.1 Jg À1 K À1 criterion agreed with the optical results while the 0.01 Jg À1 K À1 threshold lead to ademixing curve lower by 3K. Shi et al [30] identified T dem with the intersection of the two tangent lines,b elow and above the upturn in scattering intensity. T dem obtained from laser light scattering was lower by roughly 0.5 Ki nc omparison to the results acquired using their microfluidic device.Overall, the different criteria reflect an arbitrary compromise between early detection of nascent phase and experimental resolution, bearing in mind that the experimental curves vary with the sample.…”

supporting

confidence: 64%

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

2015

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In 1968, Heskins and Guillet published the first systematic study of the phase diagram of poly(N-isopropylacrylamide) (PNIPAM), at the time a "young polymer" first synthesized in 1956. Since then, PNIPAM became the leading member of the growing families of thermoresponsive polymers and of stimuli-responsive, "smart" polymers in general. Its thermal response is unanimously attributed to its phase behavior. Yet, in spite of 50 years of research, a coherent quantitative picture remains elusive. In this Review we survey the reported phase diagrams, discuss the differences and comment on theoretical ideas regarding their possible origins. We aim to alert the PNIPAM community to open questions in this reputably mature domain.

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confidence: 64%

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

2015

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“…Um Entmischungskurven zu erhalten, wurden diverse Te chniken eingesetzt:T ransmission, [16][17][18]20,22,23,[26][27][28] Intensität bei verschiedenen Streuwinkeln [24,26,[28][29][30] und Refraktometrie. Um Entmischungskurven zu erhalten, wurden diverse Te chniken eingesetzt:T ransmission, [16][17][18]20,22,23,[26][27][28] Intensität bei verschiedenen Streuwinkeln [24,26,[28][29][30] und Refraktometrie.…”

Section: Probleme Bei Der Messungunclassified

“…Afroze et al [29] verwendeten die erste Abweichung von der Grundlinie sowohl für DSC als auch für Tr ansmission und fanden, dass die optische T dem (w)-Kurve niedriger ist. Shi et al [30] identifizierten T dem mit dem Schnittpunkt der beiden Tangenten, die sich unter-u nd oberhalb des Maximums in der Streuintensität ablesen lassen. Sie identifizierten den Übergang mit 50 %T ransmission und mit dem Maximum der DSC-Endotherme.V an Durme et al [22] verwendeten als Kriterium eine 2% Tr ansmission und dazu zwei verschiedene Kriterien, um T dem aus den DSC-Messungen zu erhalten:A bweichungen von 0.01 Jg À1 K À1 oder 0.1 Jg À1 K À1 von der extrapolierten Grundlinie.D ie Entmischungstemperatur T dem ,d ie sie unter Verwendung des 0.1 Jg À1 K À1 -Kriteriums erhielten, stimmt mit dem optischen Resultat überein, während das 0.01 Jg À1 K À1 -Kriterium zu einer Entmischungskurve führte, die um 3K tiefer liegt.…”

Section: Angewandte Aufsätzeunclassified

“…Als zweites wenden wir uns optischen Messungen zu. Um Entmischungskurven zu erhalten, wurden diverse Te chniken eingesetzt:T ransmission, [16][17][18]20,22,23,[26][27][28] Intensität bei verschiedenen Streuwinkeln [24,26,[28][29][30] und Refraktometrie. [31] Die Tr ansmissions-und Intensitätsmessungen machen sich das Streulicht der Polymeraggregate zunutze,d eren Brechungsindex sich von dem der umgebenden Lçsung unterscheidet.…”

Section: Probleme Bei Der Messungunclassified

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Poly(N‐isopropylacrylamid)‐Phasendiagramme: 50 Jahre Forschung

2015

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Im Jahr 1968 publizierten Heskins und Guillet die erste systematische Studie über das Phasendiagramm von Poly(N‐isopropylacrylamid) (PNIPAM), einem zu jener Zeit “jungen Polymer”, das erstmalig 1956 synthetisiert worden war. Seitdem ist PNIPAM zu einem führenden Vertreter der wachsenden Familie temperatur‐ und reizempfindlicher Polymere geworden. Seine thermische Antwort ist fraglos durch sein Phasenverhalten begründet. Nach nunmehr 50 Jahren Forschung zeichnet sich noch immer kein einheitliches, quantitatives Bild seines Verhaltens ab. In diesem Aufsatz treten wir eine Reise zu den beobachteten Phasendiagrammen an. Wir kommentieren theoretische Überlegungen zu den möglichen Ursachen der dabei offensichtlich werdenden Unterschiede. Dabei ist es unser Ziel, nach wie vor offene Fragen auf diesem altehrwürdigen Gebiet vor Augen zu führen.

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“…Although microfluidic platforms for phase behavior studies have been demonstrated, 25–41 reported systems are only applicable to low-viscosity solutions and typically rely on phase transitions driven by composition changes due to diffusion of solutes, 25,26,33–36 evaporation of water, 28–32,40–42 and osmotic stress. 37,38 Such platforms are not suitable for the formulation of viscous mesophases with strict pre-set ratios of volume or weight of components.…”

Section: Introductionmentioning

confidence: 99%

An X-ray transparent microfluidic platform for screening of the phase behavior of lipidic mesophases

Khvostichenko

Kondrashkina

Perry

et al. 2013

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Lipidic mesophases are a class of highly ordered soft materials that form when certain lipids are mixed with water. Understanding the relationship between the composition and the microstructure of mesophases is necessary for fundamental studies of self-assembly in amphiphilic systems and for applications, such as crystallization of membrane proteins. However, the laborious formulation protocol for highly viscous mesophases and the large amounts of material required for sample formulation are significant obstacles in such studies. Here we report a microfluidic platform that facilitates investigations of the phase behavior of mesophases by reducing sample consumption, and automating and parallelizing sample formulation. The mesophases were formulated on-chip using less than 40 nL of material per sample and their microstructure was analyzed in situ using small-angle X-ray scattering (SAXS). The 220 μm-thick X-ray compatible platform was comprised of thin polydimethylsiloxane (PDMS) layers sandwiched between cyclic olefin copolymer (COC) sheets. Uniform mesophases were prepared using an active on-chip mixing strategy coupled with periodic cooling of the sample to reduce the viscosity. We validated the platform by preparing and analyzing mesophases of lipid monoolein (MO) mixed with aqueous solutions of different concentrations of β-octylglucoside (βOG), a detergent frequently used in membrane protein crystallization. Four samples were prepared in parallel on chip, by first metering and automatically diluting βOG to obtain detergent solutions of different concentration, then metering MO, and finally mixing by actuation of pneumatic valves. Integration of detergent dilution and subsequent mixing significantly reduced the number of manual steps needed for sample preparation. Three different types of mesophases typical for monoolein were successfully identified in SAXS data from on-chip samples. Microstructural parameters of identical samples formulated in different chips showed excellent agreement. Phase behavior observed on-chip corresponded well with that of samples prepared via the traditional coupled-syringe method (“off-chip”) using 300-fold larger amount of material, further validating the utility of the microfluidic platform for on-chip characterization of mesophase behavior.

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Mapping Polymer Phase Diagram in Nanoliter Droplets

Cited by 6 publications

References 24 publications

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

Poly(N‐isopropylacrylamide) Phase Diagrams: Fifty Years of Research

Poly(N‐isopropylacrylamid)‐Phasendiagramme: 50 Jahre Forschung

An X-ray transparent microfluidic platform for screening of the phase behavior of lipidic mesophases

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