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1.
Mahriah E. Alf Paul D. Godfrin T. Alan Hatton Karen K. Gleason 《Macromolecular rapid communications》2010,31(24):2166-2172
A novel thermally responsive copolymer p(NIPAAm‐co‐DEGDVE) is synthesized using the substrate independent method of iCVD and exhibits a sharp lower critical solution temperature (LCST) transition centered at ≈28.5 ± 0.3 °C determined via quartz crystal microbalance measurements with dissipation monitoring (QCM‐D). Swelling with water below the LCST produces a reversible change of ≈3× in film thickness. The layer is conformal on nanostructured surfaces including MWCNT forests and electrospun nanofiber mats. Modified planar substrates exhibit ≈30°change in static contact angle over the LCST, while through conformal coating on nanostructured substrates changes in static contact angle up to 135° are achieved. Additionally, coated surfaces exhibit temperature sensitive BSA adsorption measured by QCM‐D and is reversible as shown through fluorescence imaging of a coated electrospun nanofiber mat.
2.
Krishna C. Etika Florian D. Jochum Michael A. Cox Philipp Schattling Patrick Theato Jaime C. Grunlan 《Macromolecular rapid communications》2010,31(15):1368-1372
Poly(N‐ispropylacrylamide) [PNIPAM] is a widely studied polymer for use in biological applications due to its lower critical solution temperature (LCST) being so close to the human body temperature. Unfortunately, attempts to combine carbon nanotubes (CNTs) with PNIPAM have been unsuccessful due to poor interactions between these two materials. In this work, a PNIPAM copolymer with 1 mol‐% pyrene side group [p‐PNIPAM] was used to produce a thermoresponsive polymer capable of stabilizing both single and multi‐walled carbon nanotubes (MWNTs) in water. The presence of pyrene in the polymer chain lowers the LCST less than 4 °C and the interaction with nanotubes does not show any influence on LCST. Moreover, p‐PNIPAM stabilized nanotubes show a temperature‐dependent dispersion in water that allows the level of nanotube exfoliation/bundling to be controlled. Cryo‐TEM images, turbidity, and viscosity of these suspensions were used to characterize these thermoresponsive changes. This ability to manipulate the dispersion state of CNTs in water with p‐PNIPAM will likely benefit many biological applications, such as drug delivery, optical sensors, and hydrogels.
3.
Frank Wiesbrock Richard Hoogenboom Caroline H. Abeln Ulrich S. Schubert 《Macromolecular rapid communications》2004,25(22):1895-1899
Summary: The ring‐opening cationic polymerization of 2‐ethyl‐2‐oxazoline was performed in a single‐mode microwave reactor as the first example of a microwave‐assisted living polymerization. The observed increase in reaction rates by a factor of 350 (6 h → 1 min) in the range from 80 to 190 °C could be attributed solely to a temperature effect as was clearly shown by control experiments and the determined activation energy. Because of the homogenous microwave irradiation, the polymerization could be performed in bulk or with drastically reduced solvent ratios (green chemistry).
4.
Amphiphilic star‐shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two‐armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The “double thermosensitivity” arising both from the salt‐dependent LCST of the oligo(ethylene glycol) segments and the temperature‐responsive self‐assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid‐based smart materials.
5.
In the present paper, the microwave (MW)‐assisted synthesis of the alkaline N‐[3‐(dimethylamino)propyl]methacrylamide ( 4 ) and ‐acrylamide ( 5 ) monomers within minutes is described. The reaction was carried out by mixing and subsequent irradiation of 3‐dimethylamino‐1‐propylamine ( 3 ) and (meth)acrylic acid ( 1 / 2 ) without addition of solvent. After polymerization, the obtained homopolymers ( 6 / 7 ) exhibit lower critical solution temperature (LCST) behavior in water at 35 °C only at pH = 14. The LCST‐behavior can be influenced by N‐oxidation of the tertiary amino group with hydrogen peroxide or by formation of a polymer‐inclusion complex ( 6a ) of 6 and β‐cyclodextrin (β‐CD) by addition of randomly‐methylated β‐CD.
6.
The dextran‐allyl isocyanate/poly(N‐isopropylacrylamide) (Dex‐AI/PNIPAAm) hydrogel was designed and prepared by copolymerization of the modified dextran with N‐isopropylacrylamide (NIPAAm). This novel Dex‐AI/PNIPAAm hydrogel is biodegradable and intelligent due to its biodegradable dextran linkage and thermosensitive PNIPAAm moiety. With an increase in dextran content, it exhibits the increased lower critical solution temperature (LCST) and decreased porous microstructure. Also, the thermosensitivity of this hydrogel is also controllable and adjustable depending on the different compositions.
7.
The monomer 3‐ethyl‐1‐vinyl‐2‐pyrrolidone ( 3 ) and the homopolymer poly(3‐ethyl‐1‐vinyl‐2‐pyrrolidone) ( 5 ) have been synthesized. Polymer 5 is soluble in water and shows a critical temperature (Tc) of 27 °C. The presence of cyclodextrin causes a slight shift of the Tc. The lower critical solution temperature (LCST) could be varied between 27 and 40 °C by copolymerization with N‐vinyl‐2‐pyrrolidone. A linear correlation between the Tc and the copolymer composition is observed.
8.
Summary: N,N‐Diphenylacrylamide was polymerized in a living fashion with triisobutylaluminum in THF at 0 °C. The polymerization results showed an increase of molecular weight proportional to the amount of monomer consumed and a first‐order kinetics at −78 °C. The intermediates obtained with excess initiator at −78 °C revealed that the polymerization was initiated through 1,4‐addition of hydride from a triisobutyl group in the triisobutylaluminum and then proceeded through aluminum‐oxygen bond interchange.
9.
Novel antigen responsive hydrogels were prepared by using polymerizable antibody Fab′ fragment from monoclonal anti‐fluorescein BDC1 antibody (IgG2a). To form Fab′ containing hydrogels, the polymerizable Fab′ fragment was copolymerized with N‐isopropylacrylamide (NIPAAm) and N,N′‐methylenebis(acrylamide) (MBAAm; crosslinker) using redox initiators. The thermosensitivity of the hydrogels decreased with increasing Fab′ fragment content. The antigen responsiveness of the hydrogels depended on the Fab′ content, pH, and temperature. When the hydrogels were alternately exposed to antigens fluorescein (FL) and polyamidoamine dendrimer (PAMAM)‐fluorescein (FD), significant reversible volume changes were observed for the hydrogel containing 50% (w/w) Fab′ fragment at 33.7 and 36.8 °C in acetate buffer (10 mM , pH 5.0), respectively, but not at 27.7 °C or in PBS buffer (10 mM , pH 7.4). No noticeable reversible volume changes were observed with pure PNIPAAm hydrogel and the gel containing 10% (w/w) Fab′ fragment.
10.
Du Young Ko Hwa Jeong Lee Byeongmoon Jeong 《Macromolecular rapid communications》2006,27(16):1367-1372
Summary: The D ‐glucose imprinted core‐shell nanosphere with an average size of ≈60 to 80 nm showed a significant preference for the binding of D ‐glucose than the non‐imprinted core‐shell nanosphere. Depending on temperature, the binding site in the shell with N‐isopropylacrylamide oligomer underwent a significant change in binding affinity. In addition, the D ‐glucose imprinted core‐shell nanosphere showed a two times higher affinity for D ‐glucose than L ‐glucose, suggesting chiral recognition of the binding site. The core‐shell nanosphere reported here is a good biomimetic model system with a well‐defined morphology, high surface area, and variable binding affinity through a change in temperature.
11.
12.
Ya‐juan Wang Bao‐juan Xin Xin‐rui Duan Guo‐wen Xing Shu Wang 《Macromolecular rapid communications》2010,31(16):1473-1478
Anionic conjugated polymer (PFP‐SO) was assembled with a novel enzymatic substrate 6‐O‐modified PNP‐β‐galactoside ( 1 ) for sensitive multiplex enzyme detections. The PFP‐SO/ 1 /lipase/β‐galactosidase system has two chemical input signals which are Input 1 (lipase) and Input 2 (β‐galactosidase), and output optical signals such as fluorescence emission at 416 nm or 450 nm. Four types of logic gates, including YES, INH, NAND and AND, were successfully constructed and utilized for multiplex detections of lipase and β‐galactosidase in one tube.
13.
Jun Li Jun Jiang Chunhua Li Min Y. Lin Steven A. Schwarz Miriam H. Rafailovich Jonathan Sokolov 《Macromolecular rapid communications》2006,27(20):1787-1791
Summary: Shear‐induced orientation of nanoparticles in poly(ethylene oxide)/Laponite RD hydrogels has been investigated by small angle neutron scattering (SANS). As temperature is reduced, anisotropy develops at lower shear rates. The two‐correlation length Debye–Anderson–Brumberger (DAB) model provides a good fit to the experimental data. The deduced short‐range correlation length (≈5 nm) is observed to increase with shear. The long‐range correlation length (≈50 nm) shows a strong directional dependence, and decreases when shear is applied. The relative contribution of long‐range order to the SANS intensity is observed to increase with shear and decrease with temperature.
14.
Well‐defined PEO‐b‐PMMA was prepared, initiated by macroinitiator PEO‐Br, by means of ATRP, where esterification of the terminal hydroxyl group of PEO with 2‐bromoisobutyryl bromide yielded a macroinitiator PEO‐Br. Highly ordered microporous films (hexagonal pattern) were constructed by emulsion micelles of such amphiphilic diblock copolymer formed from a solution with CHCl3/H2O/THF = 100:5:10 (v/v). We also constructed the microporous films using diblock copolymer by the current water‐assisted method.
15.
Takakazu Yamamoto Takuma Yasuda Yoshimasa Sakai Shinji Aramaki 《Macromolecular rapid communications》2005,26(15):1214-1217
Summary: A π‐conjugated charge transfer‐type copolymer consisting of an electron‐donating thiophene and an electron‐accepting 1,3,4‐thiadiazole, P(ThdzTh), underwent facile electrochemical p‐ and n‐doping, as revealed by cyclic voltammetry. The copolymer gave a new ambipolar field‐effect transistor (FET), which showed typical IDS (source–drain current)–VDS (source–drain voltage) curves in both a p‐type working mode and an n‐type working mode. In the n‐type working mode, the polymer showed a carrier mobility of about 5 × 10−3 cm2 · V−1 · s−1 and an on/off ratio of about 3 × 104.
16.
Summary: Nanoscaled polyaniline (PANI) fibers with 17–30 nm in diameter were successfully prepared by oxidation polymerization using ferric hydrochloride (FeCl3 · 6H2O) as an oxidant in the presence of p‐toluenesulfonic acid (p‐TSA), β‐naphthalenesulfonic acid (β‐NSA), and camphorsulfonic acid (CSA) as the dopants. The resulting nanofibers show smaller diameter, higher crystallinity and conductivity (10−1 S · cm−1) compared with the nanofibers oxidized by ammonium persulfate (APS), which may be due to the lower oxidation/reduction potential of FeCl3.
17.
Francisco M. Goycoolea Angeles Heras Inmaculada Aranaz Gemma Galed María E. Fernndez‐Valle Waldo Argüelles‐Monal 《Macromolecular bioscience》2003,3(10):612-619
The ability to form a gel through the physical or chemical crosslinking of chitosan has been well documented. In an attempt to mimic biological systems, thermal and pH‐sensitive chitosan cylindrical hydrogels were produced by a combination of physical and chemical crosslinking processes. To this end, chitosan hydrogels prepared from alkali chitin were molded in cylinders and, once washed, were further crosslinked with glutaraldehyde at stoichiometric ratios, R (= [? CH?O]/[? NH2]), of 1.61 and 3.22 × 10?2. Variation in swelling as a result of stepwise changes in temperature between 40 and 2 °C at pH values of 7.0, 7.6, and 8.0 revealed that the system responds in markedly different manners dependent upon the pH. At pH 7.0, cooling from 40 to 2 °C results in contraction of the gel network structure. While raising the temperature from 2 to 40 °C leads to a rapid swelling response (i.e., ca. a twofold increase in the amount of solvent uptake). Subsequent cooling to 2 °C is accompanied by a new contraction cycle. At pH ≥ 7.6 the temperature dependence of the swelling–contraction behavior is exactly the opposite of that observed at pH 7.0. Very similar trends were observed for the gels at both degrees of crosslinking. The swelling–shrinking behavior observed in gels of pH ≥ 7.6, is similar in kind to that of uncrosslinked gels and is interpreted in terms of a lower critical solution temperature (LCST) volume phase transition, driven by hydrophobic association, presumably involving residual acetyl groups in the chitin. The results at pH 7.0 suggest that the slight ionization of the ? NH groups leads to destruction of the hydrophobic hydration thus effectively reversing the negative thermal shrinking.
18.
Xiao‐Ding Xu Chang‐Sheng Chen Bo Lu Zong‐Chun Wang Si‐Xue Cheng Xian‐Zheng Zhang Ren‐Xi Zhuo 《Macromolecular rapid communications》2009,30(3):157-164
Two kinds of representative polymers, poly(N‐isopropylacrylamide) (PNIPAAm) and β‐cyclodextrin (β‐CD) were selected and modified with azide and alkyne fucntional groups, respectively. When the solutions of these two modified polymers were mixed together, a cross‐linking reaction, a type of Huisgen's 1,3‐dipolar azide‐alkyne cycloaddition, occurred in the presence of Cu(I) catalyst. The strategy described here provides several advantages for the hydrogel formation including mild reaction conditions and controllable gelation rate. The resulted hydrogels were studied in terms of scanning electric microscopy (SEM), equilibrium swelling ratio and swelling/shrinking kinetics. The data obtained demonstrated the hydrogels had a porous structure as well as favorable thermosensitivity.
19.
Yasushi Maeda Hiroki Mochiduki Isao Ikeda 《Macromolecular rapid communications》2004,25(14):1330-1334
Summary: Thermosensitive association of a diblock copolymer consisting of poly(3‐dimethyl(methacryloyloxyethyl) ammonium propane sulfonate) (PdMMAEAPS), as an upper critical solution temperature (UCST) block, and poly(N,N‐diethylacrylamide) (PdEA), as a lower critical solution temperature (LCST) block, has been investigated by using IR spectroscopy. The ν(CO) and ν(SO) bands of the PdMMAEAPS block and the amide I band of PdEA block critically changed at the UCST and LCST, respectively, indicating that the segmental interaction of each block is altered at each transition.
20.
Meihua Jin Xinjian Feng Jinming Xi Jin Zhai Kilwon Cho Lin Feng Lei Jiang 《Macromolecular rapid communications》2005,26(22):1805-1809
Summary: Rough polydimethylsiloxane (PDMS) surface containing micro‐, submicro‐ and nano‐composite structures was fabricated using a facile one‐step laser etching method. Such surface shows a super‐hydrophobic character with contact angle higher than 160° and sliding angle lower than 5°, i.e. self‐cleaning effect like lotus leaf. The wettabilities of the rough PDMS surfaces can be tunable by simply controlling the size of etched microstructures. The adhesive force between etched PDMS surface and water droplet is evaluated, and the structure effect is deduced by comparing it with those own a single nano‐ or micro‐scale structures. This super‐hydrophobic PDMS surface can be widely applied to many areas such as liquid transportation without loss, and micro‐pump (creating pushing‐force) needless micro‐fluidic devices.