Summary: In order to achieve a reasonable response time in an electrochromic display, viologen‐modified porous polymeric microspheres of various porosities have been used as substrates. Porous microspheres are prepared using seeded polymerization in the presence of a porogen. Based on ionic conductivity and the chronocoulometry measurements, it is confirmed that the electrolyte content increases, and the resistance of the polymer particles in the device decreases as the specific surface area of the porous particles increases. This results in a rapid response time of 270 ms.
Schematic representation of the viologen‐modified porous polymeric microspheres in the manufactured ECD device (A). Images of the device (B) in the OFF state (left) and in the ON state (right). 相似文献
Summary: Magnetic nanoparticles have been prepared by a co‐precipitation method and modified with methacryloxypropyltrimethoxysilane. Magnetic molecularly imprinted polymer particles have been prepared by suspension polymerization in silicone oil. The particles possess a high affinity to the template molecules and are rapidly separated under a magnetic field.
Summary: Monodisperse thermosensitive PS‐NIPA core‐shell particles composed of a PS core and a cross‐linked PNIPA shell can be successfully synthesized by a novel method: photoemulsion polymerization. Cryo‐TEM images indicate clearly the core‐shell morphology of the PS‐NIPA particles: A homogeneous regular PNIPA shell has been affixed on the spherical PS core. DLS measurements indicate that the obtained PS‐NIPA latex particles are thermosensitive. The shell of PNIPA networks with different cross‐linking densities can shrink and re‐swell with temperature and the volume transition temperature is around 32 °C in all cases.
Cryo‐TEM image of PS‐NIPA core‐shell particles. 相似文献
Dispersion polymerization of n‐butyl acrylate has been performed in a mixture of ethanol and water in the presence of poly(N‐acryloylmorpholine) (polyNAM). These hydrophilic polymer chains are synthesized by the RAFT process and thus incorporate well‐defined chain ends. The dithioester ω‐end group is used as an efficient chain transfer agent under dispersion polymerization conditions to produce hairy poly(n‐butyl acrylate) latex particles. Moreover, pre‐functionalization of the polyNAM chains on the α‐end by a carbohydrate derivative is also achieved to obtain directly functionalized particles according to the same strategy.
Summary: Latices with “core-shell” particle morphology containing polar “core” and a shell on the basis of copolymer of styrene and functional vinyl monomer (allyl alcohol, vinyl acetate, methacrylic acid) has been obtained as a result of graft-copolymerization initiated from the surface of (meth)acrylate latex particles previously modified with functional polyperoxides. The processes of functional shell grafting as well as the processes of latex particle swelling with obtaining hollow microspheres due to neutralization of core carboxylic groups have been studied. 相似文献
The dependence of quality indicators of cotton cellulose obtained by an oxygen-alkaline digestion method, cellulose from the Bakai company, and wood cellulose on their supramolecular and morphological structure was studied by various physicochemical methods. The number of gel particles in cellulose solutions depends on their degree of polymerization; in solutions of their Na-CMC esters, on the content of the primary fiber wall of the starting cellulose相似文献
Poly(styrene-co-methacrylic acid) [P(St-co-MAA)] microspheres were prepared by emulsifier-free emulsion copolymerization of St with MAA. Fourier transform IR spectroscopy
and elemental analysis were used to study the change in the content of MAA in the microspheres. The results of X-ray photoelectron
spectroscopy measurements indicated the presence of carboxylic functionality on the surface of the microspheres. The P(St-co-MAA) metal composite particles were prepared by chemical metal deposition. Transmission electron microscopy observation and
X-ray diffraction measurement were used to study the distribution and structure of the metal particles deposited.
Received: 15 September 1999 Accepted: 24 December 1999 相似文献