Molecular design of three-dimensional artificial extracellular matrix: Photosensitive polymers containing cell adhesive peptide

A photodimerizable monomer, methacrylic acid-(7-coumaroxy) ethyl ester, was synthesized and was copolymerized with a hydrophilic monomer (N,N-dimethylacrylamide) to obtain a water-soluble photosensitive polymer. Irradiation of the copolymer film and aqueous solution with a high-pressure mercury lamp resulted in highly hydrated gel. The gel yield was enhanced with the content of the photodimerizable group in the copolymer and the irradiation time. The degree of swelling of the gels decreased concomitantly. Incorporation of the well-known cell adhesive peptidyl ligand Arg-Gly-Asp-Ser(RGDS) into photosensitive copolymers attained a biologically active hydrophilic gel matrix upon UV light irradiation. Irradiation of a buffer solution of the latter copolymer premixed with smooth muscle cells entrapped the cells throughout the gel matrix. This indicates that the designed polymer and the resulting cell-incorporated hydrogel are biomimic to an extracellular matrix and to the media of the vascular wall, respectively. © 1993 John Wiley & Sons, Inc.     

Light-energy conversion systems for hydrogen production and photocurrent generation using zinc chlorin derivatives

To develop efficient systems for light-energy conversion, monomeric and dimeric zinc chlorin derivatives were synthesized. These derivatives act as photosensitizers for light-induced hydrogen production with methylviologen as the electron mediator and Pt nanoparticles as the hydrogen-evolution catalyst. The monomeric derivative exhibited ~1.5-times higher activity than the dimeric derivative. The photocurrent-generating activity of the Zn chlorin derivatives assembled on a chemically modified indium tin oxide electrode was investigated; the dimeric derivative exhibited significant activity compared to the monomeric derivative. The photosensitizing activity of the derivatives in dye-sensitized solar cells was also investigated. The dimeric derivative exhibited two-fold higher performance than the monomeric derivative. The dimerization effect on the photosensitizing activities is briefly discussed in terms of stacking conformations based on the results of absorption and fluorescence spectroscopies.     

Radiation-Induced Polymerization of Acrylic Esters at High Pressure and Pressure-Volume Behavior of Polymer-Monomer Coexistence System as Polymerized

Pressure-volume (P-V) behavior and radiation-induced polymerization of methyl and n-butyl acrylic esters (MA and BA, respectively) were studied up to 7000 kg/cm² at 20°C. The P-V isotherms broke at 1900 and 1200 kg/cm² for MA and BA, respectively. The P-V isotherm for MA was not smooth in the pressure range between 3500 and 4000 kg/cm². The polymerization behavior varied with change in the P-V behavior; the polymerization rates were maximum at 1800 kg/cm for MA and 1000 kg/cm² for BA, and then minimum at 1900 kg/cm² for MA and 1100 kg/cm² for BA. The polymerization rates increased again above the pressures giving the minimum rates up to about 3000 kg/cm². Above 3000 kg/cm² the pressure dependence of the rates decreased up to 4000 and 4500 kg/cm² for MA and BA, respectively. Above these pressures, the pressure dependence of polymerization rates increased again. The P-V isotherms of as-polymerized polymer-monomer coexistence systems showed characteristic behavior near the polymerization pressure. From a comparison of these polymerizations and P-V behavior with those of methacrylic esters, we propose that acrylic esters align at high pressure and that freedom of rotation of ester group plays an important role in the mode of pressure-induced alignment of monomer molecules.     

Indium-mediated chemoselective deprotection and demonochlorination of 2,2,2-trichloroethyl esters

On treatment with indium metal, the 2,2,2-trichloroethyl carboxylates smoothly undergo deprotection to carboxylic acids and reductive demonochlorination to 2,2-dichloroethyl esters, sharply depending on their structures.     

Controlled self‐assembly of porphyrin/fullerene donor–acceptor complex in a polymer thin film

Thin films composed of polycyclohexane (PCHE), zinc(II)‐5,10,15,20‐tetra‐(2‐naphthyl)porphyrin (ZnTNpP), and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) blends are prepared to investigate their potential for the controlled self‐assembly of a porphyrin/fullerene donor–acceptor complex in a polymer thin film. The compatibilities of PCHE/PCBM (p), PCHE/ZnTNpP (q), and ZnTNpP/PCBM (r) in these blends have a significant effect on the dispersion of the ZnTNpP/PCBM donor–acceptor complex in the PCHE thin film. When the compatibilities are p << q, r, and q ≈ r, the ZnTNpP/PCBM donor–acceptor complex is formed between the PCHE and PCBM phases. This concept to form a controlled self‐assembly of the ZnTNpP/PCBM donor–acceptor complex may be applied to various combinations of porphyrin/fullerene systems in polymer thin film solar cells to achieve excellent performance. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 743–746     

Novel Copolymers of 4-Fluorostyrene. 2. Alkoxy Ring-Substituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, alkoxy ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₄CH = C(CN)₂ (where R is 2-methoxy, 3-methoxy, 4-methoxy, 2-ethoxy, 3-ethoxy, 4-ethoxy, 4-propoxy, 4-buthoxy, 4-hexyloxy) and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r ₁) for the monomers is 2-methoxy (1.5) > 4-ethoxy (1.0) > 4-methoxy (0.8) > 3-ethoxy (0.7) = 3-methoxy (0.7) > 4-hexyloxy (0.6) = 2-ethoxy (0.6) > 4-butoxy (0.5) = 4-propoxy (0.5). High T _g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in 284–500°C range with residue (5–9% wt), which then decomposed in the 500–800°C range.     

Novel Copolymers of 4-Fluorostyrene. 8. Some Ring-Trisubstituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₂CH=C(CN)₂ (where R is 2,4-(CH₃O)₂-3-CH₃, 2,3,4-(CH₃O)₃, 2,4,5-(CH₃O)₃, 2,4,6-(CH₃O)₃, 3,4,5-(CH₃O)₃, 6-Br-3,4-(CH₃O)₂), 2,3,5-Cl₃, 2,3,6-Cl₃ and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r ₁) for the monomers is 3,4,5-(CH₃O)₃(10.6) > 2,4,6-(CH₃O)₃(9.3) > 2,4,5-(CH₃O)₃ (5.4) > 2,3,4-(CH₃O)₃ (4.4) > 6-Br-3,4-(CH₃O)₂ (3.2) > 2,3,5-Cl₃ (1.5) > 2,3,6-Cl₃ (1.0) > 2,4-(CH₃O)₂-3-CH₃ (0.7). High T _g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–400°C range with residue, which then decomposed in the 400–800°C range.     

Novel Copolymers of Styrene and Some Halogen Ring-substituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₃CH═C(CN)₂ (where R is 2-bromo,3-bromo, 3-chloro, 2,3-dichloro, 2-chloro-6-fluoro, 2,6-difluoro, 3,4-difluoro, and 3,5-difluoro) and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR, GPC, DSC, and TGA. High T _g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 200–800°C range.