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We have prepared nanoporous polystyrene (PS) samples using a solvent extraction method starting from a solid sample with a mixture of high and low molecular weights. The resulting nanoporous samples are characterized using ellipsometry, atomic force microscopy and electron microscopy. This method can potentially be applied to many different polymer materials.
The mean-square radius of gyration 〈S2〉 is determined for poly(di-tert-butyl fumarate) (PDtBF) for a range of weight-average number of repeat units nw from 382 to 1520 in tetrahydrofuran at 30.0 °C. The data are analyzed on the basis of the Kratky–Porod (KP) wormlike chain with excluded volume (EV). It is shown that the average chain dimension of PDtBF is significantly larger than that of poly(diisopropyl fumarate) (PDiPF) because of a remarkable difference in chain stiffness between the two polymers.
Fullerenes (C60 and C70) and water-soluble poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) were mixed by physical means to prepare water-soluble fullerene/PMPC complexes. PMPC can solubilize large amounts of fullerenes in water. The complexes can generate singlet oxygen upon visible light irradiation.
This paper describes the synthesis of hyperbranched poly(siloxysilane) grafted poly(N-isopropylacrylamide) (HBPS-g-PNIPAM), and its application to thermoresponsive cell culture onto glass substrate. PNIPAM branches were growth from the termini of HBPS via reversible addition–fragmentation chain transfer (RAFT) polymerization. The obtained HBPS-g-PNIPAM was casted from a tetrahydrofuran (THF) solution onto glass slides to fabricate a thermoresponsive surface for cell culture. Mouse 3T3 fibroblast cells were seeded and cultured at 37 °C for 4 days and detachment was possible by cooling the temperature to 20 °C for 15 min.
Five asymmetric diacetylene carbamates that possessed a 9-phenyl-9H-carbazol-3-yl (PhCz) group as an aromatic donor that was directly attached to the diacetylene moiety were designed and synthesized. Upon UV irradiation, the highest conversion to the corresponding polydiacetylene was obtained for the benzyl carbamate derivative, and its regular 1,4-addition was confirmed by formation of a greenish-blue polymer that exhibited characteristic excitonic absorption bands. In addition, a small ionization potential of 5.2 eV was observed for this polydiacetylene.
Free-standing calcite thin films containing a few wt% of organic polymer were obtained through repeated cycles of layer-by-layer deposition of the vaterite particles stabilized with an octacarboxy-terminated T8-caged silsesquioxane, followed by a phase transition to calcite, after a poly(diallyldimethylammonium chloride) (PDDA) layer or a multilayer of PDDA with poly(sodium 4-styrenesulfonate) were coated on the surface of the calcite thin films. Poly(allylamine hydrochloride) and poly(acrylic acid) were also applied for preparing calcite thin films on a glass substrate.
Surface carboxylation of cellulose nanowhiskers (CNWs) was performed using mPEG2000-TEMPO, a 2,2,6,6-tetramethyl-1-piperidinyloxy radical moiety grafted to monomethoxy poly(ethylene glycol) 2000. After the oxidation step, the used mPEG2000-TEMPO was recovered by extraction with dichloromethane and reused for further oxidation cycles. mPEG2000-TEMPO could be used for the surface oxidation of CNWs for at least three repeated cycles, although the degree of oxidation in the second and third cycles was reduced to 60% of that in the first cycle. The recovery of mPEG2000-TEMPO after every cycle was not complete (~80%), thus suggesting an irreversible adsorption of mPEG2000-TEMPO on the surface of the CCNWs.
This paper demonstrates a simple method for the preparation of poly(vinylidene fluoride) (PVDF) films using the antisolvent addition method. The antisolvent addition method was performed by immersing PVDF solution-casted substrates into the antisolvent for PVDF at room temperature for a few minutes. After immersing and drying for a few hours, a PVDF film was easily obtained. Then, the crystalline structure of the resulting PVDF film was changed in the order of α, γ and β phases with increasing dipole moment of the solvent.
