Block copolymers remain one of the most extensively studied and utilized classes of macromolecules due to their extraordinary abilities to (i) self-assemble spontaneously into a wide variety of soft nanostructures and (ii) reduce the interfacial tension between, and thus compatibilize, immiscible polymer pairs. In bilayered thin-film laminates of immiscible homopolymers, block copolymers are si...

Block junctions are the topological constraints of connecting two homopolymers of different species to form diblock copolymers, which make the phase transition behaviors of diblock copolymers deviate from that of parallel polymer blends. We performed dynamic Monte Carlo simulations of these two parallel polymeric systems to compare their behaviors in the interplay of phase transitions. The resu...

Two-dimensional, hierarchical assemblies of nanorods were obtained by exploiting the structures afforded by block copolymers in ultrathin films. Under the appropriate conditions, the nanorods segregate to the film surface already upon casting the composite film, and organize with the block copolymer through phase separation. In this paper we compare the structures formed by CdSe nanorods of thr...

Microparticles or nanospheres of hydrogels of crosslinked poly(methacrylic acid) grafted with poly(ethylene glycol) as well as crosslinked poly(acrylic acid) grafted with poly(ethylene glycol) were prepared for use as oral insulin delivery carriers. The copolymer carriers were synthesized by precipitation/dispersion polymerization that led to gel nanospheres or by bulk polymerization and subseq...

We describe a simulation method to design surfaces for recognizing specific monomer sequences in copolymers. We fix the monomer sequence statistics of the AB copolymers on a surface containing two types of sites and allow the simulation to iterate towards an optimal surface pattern that can recognize and selectively adsorb the sequence in the copolymer. During the simulation the surface pattern...

The conformations adopted by random copolymers of two components adsorbed on a flat surface are studied by the use of a simulation technique. The simulation technique is based on the analytical equilibrium calculation of the Cluster Variational Method and is a generalization of the Cluster Growth Probability Method to the case when the probabilities include chemical bonds. The model used here a...

The aims of our study were to assess the release of cytotoxic nucleoside analogs 5-fluorouracil and 2-chloro-2'-deoxyadenosine from different lactide-glycolide or lactide-caprolactone biodegradable copolymers and the effects of sterilization on this release. The polymers were sterilized either with ethylene oxide at 37 degrees C, or with gamma radiation (15 kGy, 20 kGy, or 25 kGy). The kinetics...

We consider orientation mechanisms for block copolymers in an electric field. Theoretical and experimental studies have shown that nonuniformity of the dielectric constant gives rise to a preferred orientation of the melt with respect to the applied field. We show that the presence of ions, as found in anionically prepared copolymers, may increase the alignment effect markedly. Time-varying (ac...

The synthesis and characterization of complex dendritic, rigid rod poly-2,7-fluorene homopolymers and copolymers via a macromonomer approach is reported. Several 2,7-dibromofluorene monomers containing benzyl ether dendrons (generations 1, 2, and 3) in the 9,9'-position of the fluorene ring were prepared and employed in condensation polymerizations to yield both homopolymers and copolymers with...

Synthesis, characterization and cytotoxicity evaluation of copolymers based on polyethylene glycol monmethyl ether-g-poly(methacrylic acid-co-methyl methacrylate) are reported via a polymeric precursor method. Grafting was accomplished based on direct condensation reaction in the presence of dicyclohexylcarbodiimide as an esterification-promoting agent catalyzed by dimethylamino pyridine. Polye...