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A new water-soluble fluorescent conjugated polyelectrolyte, poly[9,9-bis(3′-butyrate)fluoren-2,7-yl] sodium (BBS-PF), was studied as a fluorescent probe for protein sensing. The conjugated polyelectrolyte BBS-PF shows high fluorescence sensitivity to cytochrome c, lysozyme, and bovine serum albumin (BSA). The Stern–Volmer constant (Ksv) in cytochrome c was measured to be as high as 6.1 × 107 L/mol, approximately twice as that of the other two. Interestingly, it is found that BSA slightly enhances the fluorescence of BBS-PF rather than quenches the fluorescence at its micromolar concentrations. The excitation spectra confirm that the interaction of BBS-PF with the proteins could be different. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

This work describes a comprehensive study of hydrogels based on polyethylene glycol diacrylates (PEGDAs) with the molecular weight (MW) range of 400–2000. The blends of low- and high-molecular weight PEGDA macromers with different ratios were photopolymerized under visible light irradiation, using a blue light sensitive photoinitiator Irgacure819, at the total polymer concentration of 60 wt %. Swelling ratios, wetting property, elastic moduli, transparency, and the microstructure of the resulting hydrogels were investigated. Among them, equilibrium water contents, hydrophilicity, and mesh size of the hydrogels increased while the elastic moduli decreased when increased the PEGDA MW or the content of higher MW PEGDA in the blends. Most of the hydrogels possessed excellent transparency in visible region. The viability of L929 cells on the surface of hydrogel was also estimated. All the selected hydrogels exhibited a relatively high proliferation rate, which demonstrated this hydrogel system with photoinitiator Irgacure819 had good biocompatibility. These results show the properties of PEGDA hydrogel could be easily adjusted by varying PEGDA MW or the ratios of low- and high-MW macromers in the composites. It could be helpful for the design of proper PEGDA hydrogels in the applications as tissue engineering or drug delivery system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The synthesis of poly(2-methoxy-5-n-butoxy-p-phenylene vinylene) (MBPPV) via a dehydrochlorination of 2-methoxy-5-n-butoxy-α,α-dichloro-p-xylene is described. The soluble polymer was characterized by elemental analysis, Fourier transform infrared (FTIR), 1 H nuclear magnetic resonance (NMR), and UV-visible spectroscopy. The energy gap (Eg) of the polymer was 2.53 eV determined by cyclic voltammogram. Light-emitting diode (LED) and light-emitting electrochemical cell (LEC) with the polymer were fabricated. The LED displayed unipolar I-V dependence with the turn-on voltage at 4.2 V. I-V curve of the LEC with poly(ethylene oxide) (PEO, Mw 2 × 10 4 ) displayed mirror symmetry with the turn-on voltage at 2.7 V, but to the device with PEO (Mw 5 × 10 6 ) no mirror symmetry was observed, the turn-on voltages at +2.7 V, -11.5 V. The emission maximum of the polymer in chloroform was at A = 550 nm, whereas the emission maxima of the LED at 5.2 V and the LEC at 4.8 V were at A = 566, 569 nm, respectively.

The mechanical properties of the water-swellable rubber prepared by blending polychloroprene with precipitated silica, crosslinked sodium polyacrylate, polyethylene oxide, and vulcanizing agents—such as stress at break, strain at break, modulus, energy at break, and hardness—were studied before and after swelling with water. The results showed that the addition of the reinforcing filler (precipitated silica) increased the mechanical properties, while adding crosslinked sodium polyacrylate decreased the mechanical properties, although it could improve water-absorbent properties of the water-swellable rubber. If some polyethylene oxide was included in the rubber formulation, the water-absorbent properties and the mechanical properties of the rubber both increased; but, with the increase of more polyethylene oxide, the mechanical properties decreased. Wide-angle X-ray diffracting analysis was conducted to study the crystalline behavior of the rubber, which showed that the crystallinity of the vulcanized polychloroprene increased first and then decreased with an increase in the amount of polyethylene oxide. The crosslink density of the rubber was calculated by the Flory–Rehner equation. The mechanical strength of the rubber significantly decreased after swelling with water, compared with that before swelling with water. The morphology of blends was shown by scanning electron microscopy graphs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 577–584, 1999

A water-swellable rubber was prepared by blending polychloroprene (CR) with crosslinked sodium polyacrylate (CSP), precipitated silica, poly(ethylene oxide) (PEO), and vulcanizing agents. The preparation process was described and the effect of composition of the water-swellable rubber on its water-absorbent properties such as degree of swelling, swelling rate, and weight loss ratio of CSP was discussed and the optimum composition range was identified: CSP, 25–75 phr; precipitated silica, 10–50 phr; and PEO, 5–30 phr. The reinforcing filler (precipitated silica) and the water-soluble polymer (PEO) were found to improve the water-absorbent properties of water-swellable rubber. The morphology of CSP and the silica in the rubber was studied by scanning electron microscopy, which showed that they were well dispersed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1219–1225, 1998

A superwater-absorbent sodium polyacrylate was synthesized by inverse suspension polymerization, using Span60 as the dispersant, cyclohexane as the organic phase, N,N′-methylene bisacrylamide as the crosslinking agent, and potassium persulfate as the initiator. The effect of reaction conditions such as reaction time, crosslinking agent, and dispersant on deionized-water and saline solution absorbability, average particle size, and distribution of the sol–gel of the resin is discussed. The deionized-water and saline solution absorbabilities of sodium polyacrylate prepared at proper conditions were 300–1200 and 50–120, respectively; the number-average particle size was 10–50 μm and the gel portion was 20–85% by weight. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 789-794, 1997

Poly(dimethylaminoethyl methacrylate) hydrogels containing cholic acid (PDMAEMA–CA) were synthesized by radiation crosslinking. The introduction of 10 and 20 mol% cholic acid (CA) into the poly(dimethylaminoethyl methacrylate) (PDMAEMA) hydrogel decreased the maximum swelling ratio (SR) of the gel from 40 to 6 and 5, respectively. The incorporation of CA with dimethylaminoethyl methacrylate led to a decrease in the lower critical swelling temperature of the gel from 44 to 42°C but did not exert big influence on the ion-stimulus-responsive properties of the gel. However, the pH sensitivity of the PDMAEMA–CA gel was quite different from that of PDMAEMA gel. The SR of PDMAEMA gel decreased at pH 2.5, whereas the SRs of the PDMAEMA–CA gels showed a convex-upward function of pH; that is, SR of the PDMAEMA–10% CA gel first increased (pH 1.2–3.2) and then decreased (pH 3.2–11.9) with increasing pH. The pH-stimulus-responsive swelling behavior of the PDMAEMA–20% CA gel was similar to that of the PDMAEMA–10% CA gel except for the unique swelling behavior exhibited in the lower pH region. The unique decrease in SR in strong acidic solutions was attributed to aggregations driven by the hydrophobic interactions between CA molecules. Phase separation of the gel in strongly acidic solutions was observed; that is, the margin of the swollen gel was transparent and elastic (cellular structure), whereas the core of it was opaque (aggregated structure) as recorded by scanning electron microscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39998.