Thermosensitive poly(allylamine)-g-poly(N-isopropylacrylamide): synthesis, phase separation and particle formation

Gao, Changyou; Möhwald, Helmuth; Shen, Jiacong

doi:10.1016/j.polymer.2005.02.115

Cited by 53 publications

(38 citation statements)

References 40 publications

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“…Different from many block copolymers, previously we have synthesized a grafting copolymer of PAH and PNIPAAm, i.e., PAH-gPNIPAAm. [22][23][24] Experimental results show that the LCST (34 8C) of this polymer is not influenced by the PAH segment, which is of great help to design the building blocks and thereby to control the properties of the resulting multilayers. In this work, we report the preparation of PAHg-PNIPAAm/poly(styrene sulfonate) sodium salt (PSS) multilayer films.…”

Section: Introductionmentioning

confidence: 89%

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Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide)/Poly(styrene sulfonate) Sodium Salt Multilayers: Buildup, Wettability, and Mechanical Properties

Wang

Gao

2009

Macro Chemistry & Physics

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Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide) (PAH‐g‐PNIPAAm)/poly(styrene sulfonate) sodium salt (PSS) multilayer films are prepared using electrostatic layer‐by‐layer assembly. Buildup of the PAH/PSS and PAH‐g‐PNIPAAm/PSS multilayers under different salt concentrations and different temperatures is compared by using ellipsometry and scanning force microscopy. All the film thicknesses increase linearly with the increase of layer number regardless of their assembly conditions. However, the average layer thickness of the PAH‐g‐PNIPAAm/PSS multilayers is larger than that of the PAH/PSS multilayers under the same assembling conditions. Their surfaces also become rougher and show higher water contact angles. In contrast to the apparent loss transition in the friction force curve of the PAH/PSS multilayers, the PAH‐g‐PNIPAAm/PSS multilayers with PAH‐g‐PNIPAAm as the outmost layer do not undergo a pressure‐induced glass transition in water. Nanoindentation tests show that the elastic modulus of the PAH‐g‐PNIPAAm/PSS multilayers is only 75% of that of the PAH/PSS multilayers.magnified image

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Section: Introductionmentioning

confidence: 89%

“…The PAH-g-PNIPAAm copolymer was synthesized by grafting carboxylic end-capped PNIPAAm (PNIPAAm-COOH, MW 2.5 kD) onto PAH chains as described previously. [22] The grafting degree of PNIPAAm was measured as 33 by elemental analysis. For brevity, this PAH-g-PNIPAAm copolymer is denoted as PN33.…”

Section: Experimental Partmentioning

confidence: 99%

Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide)/Poly(styrene sulfonate) Sodium Salt Multilayers: Buildup, Wettability, and Mechanical Properties

Wang

Gao

2009

Macro Chemistry & Physics

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“…30 In brief, 1 g of the recrystallized monomer NIPAAm and 0.02 g of azodiisobutyronitrile were dissolved in 25 mL of methanol in a three-neck flask, then 50 µL of MPA was added into the mixture. The reaction was bubbled with nitrogen atmosphere at 60°C for 24 hours (h).…”

Section: Synthesis Of Ha-g-pnipaam Synthesis Of Pnipaam-coohmentioning

confidence: 99%

Enhanced and sustained topical ocular delivery of cyclosporine A in thermosensitive hyaluronic acid-based in situ forming microgels

Wu¹,

Yao²,

Zhou³

et al. 2013

IJN

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“…On the other hand, the flat region disappeared in the spectrum of PNIPAAm PAA probably because of the weak characteristic absorption band (ca. 1050 cm ¹1 ) 30 assignable to CN stretching of primary amines. The occurrence of the flat portion in the spectrum of PNIPAAmPIDA can be ascribed to the almost complete conversion of primary amines to IDA groups.…”

Section: Resultsmentioning

confidence: 99%

Preconcentration of Trace Metals in Water Using a Newly Designed Thermoresponsive Chelating Polymer for the Sensitive Determination by Graphite Furnace Atomic Absorption Spectrometry

Saitoh

Arakawa

Hiraide

2013

Bulletin of the Chemical Society of Japan

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A thermoresponsive polymer containing highly dense iminodiacetic acid segments was newly designed for the efficient preconcentration of trace metals in water. The polymer was synthesized by the water-soluble carbodiimidemediated condensation of poly(N-isopropylacrylamide-co-acrylic acid) with polyallylamine and the subsequent conversion of amino groups to iminodiacetic acid. Metal ions in water were collected by adding the thermoresponsive polymer, sodium nitrate, dodecyltrimethylammonium chroride, and buffer components and then heating the resulting solution to form polymer deposits. The use of 0.02% (w/v) thermoresponsive polymer allowed the nearly complete (>99.8%) collection of seven metals (Be, Co, Ni, Cu, Cd, In, and Pb) in the pH range of 6.88.3. The polymer deposits were readily collected as a condensed coagulate and dissolved with a small amount of water for the analysis by graphite furnace atomic absorption spectrometry. Because of highly efficient (100-fold) concentration, these metals at pg cm ¹3 ng cm ¹3 levels were successfully determined. The precision and accuracy were evaluated by analyzing certified reference water samples.Graphite furnace atomic absorption spectrometry (GFAAS) has extensively been used for the determination of trace metals in different water samples, because of its high sensitivity, specificity, accuracy, and versatility in the analysis. However, suitable preconcentration methods are often necessary for the accurate determination of ultra-trace amounts of metals in environmental waters. Chelating ion-exchangers, 13 reagentimmobilized sorbents, 47 and synthetic zeolite 8 have been employed for this purpose. The formation of metal chelates followed by the sorption onto polymer beads, 9,10 C18-bonded silica gels, 1113 and surfactant-coated sorbents (hemi-micelles or admicelles) 1416 were potentially useful as more efficient preconcentration methods. In these methods, however, sample solutions should be passed through sorbent-packed columns, which is often tedious and time-consuming. Furthermore, the elution of trace metals is often insufficient because of irreversible sorption.An attractive alternative may be a polymer-mediated extraction of hydrophobic metal chelates. 17,18 That is based on the thermoresponsive precipitation phenomenon of a water-soluble polymer, poly(N-isopropylacrylamide) [PNIPAAm] or poly-(methyl vinyl ether), above its lower critical solution temperature (LCST, ca. 32°C 1921 ). During the precipitation, hydrophobic substances in the aqueous solution can be solubilized and incorporated into the polymer assembly. For the application to the concentration of trace metals, the polymer-mediated extraction was conducted after converting metal ions into hydrophobic chelates with appropriate chelating agents. Since the polymer aggregates were condensed to an extremely small volume, the desired metal chelates were highly concentrated. At room temperature the polymer aggregates were redissolved with a small amount of polar solvent. The resulting solution was succ...

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Thermosensitive poly(allylamine)-g-poly(N-isopropylacrylamide): synthesis, phase separation and particle formation

Cited by 53 publications

References 40 publications

Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide)/Poly(styrene sulfonate) Sodium Salt Multilayers: Buildup, Wettability, and Mechanical Properties

Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide)/Poly(styrene sulfonate) Sodium Salt Multilayers: Buildup, Wettability, and Mechanical Properties

Enhanced and sustained topical ocular delivery of cyclosporine A in thermosensitive hyaluronic acid-based in situ forming microgels

Preconcentration of Trace Metals in Water Using a Newly Designed Thermoresponsive Chelating Polymer for the Sensitive Determination by Graphite Furnace Atomic Absorption Spectrometry

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