The formation of micelles in 1-butyl-3-methyl imidazolium chloride (BMIM-Cl) and hexafluorophosphate (BMIM-PF6) were explored using different surfactants and the solvation behavior of the new micellar-ionic liquid solutions examined using inverse gas chromatography.

A novel approach is presented for manipulating the size and chemistry of nanoscopic features using a combination of contact molding and living free radical polymerization. In this approach a highly cross-linked photopolymer, based on a methacrylate/acrylate mixture, was patterned into submicrometer-sized features on a silicon wafer using a contact-molding technique. A critical component of the monomer mixture was the incorporation of an initiator containing monomer into the network structure, which provides sites for functional group amplification. Features ranging in size from 5 microm to <60 nm were accurately replicated by this process and living free radical polymerizations, both atom transfer radical and nitroxide-mediated polymerization (NMP), could be conducted from these initiating sites to yield polymer brushes which represent a grafted layer of linear chains attached to the original network polymer. Grafts consisting of polystyrene, poly(methyl methacrylate), and poly(2-hydroxyethyl)methacrylate were grown with controlled thicknesses ranging from 10 to 143 nm and graft molecular weights of between 18 000 to 290 000 amu. As a result of this secondary graft process, feature sizes could be tuned from the original 100 nm down to 20 nm, and the surface chemistry varied from hydrophilic to hydrophobic starting from the same initial master pattern. The thin films and patterned features were characterized by contact angle, ellipsometry, optical, and atomic force microscopies.

Novel pH-sensitive gel-forming pentablock copolymers based on commercially available Pluronic (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), PEO-b-PPO-b-PEO) triblock copolymers and cationic diblock copolymers based on polyethylene glycol) methyl ether (PEGME) were synthesized by oxyanionic polymerization. Polymerization of the cationic moiety, poly((diethylamino)-ethyl methacrylate), PDEAEM, was initiated by a difunctional potassium alcoholate of the triblock Pluronic copolymer F127 (PEO106-PPO69-PEO106) or PEGME. The difunctionality of the initiation using the triblock macroinitiator, indicating formation of a pentablock copolymer rather than a tetrablock copolymer, was verified by functionalized termination of the living polymer chains. Critical micellization temperatures (cmt) of the synthesized polymers were obtained from differential scanning calorimetry for the pentablock materials. The pentablock copolymers retained the thermoreversible gel-forming properties of Pluronic F127 as well as similar cmt values. The polydispersity of both the diblock and pentablock copolymers was similar to the macroinitiators, indicating a very low polydispersity associated with the addition of the cationic PDEAEM blocks. Both of the materials show pH-sensitive release behavior, whereas the native polymers do not. ABSTRACT: Novel pH-sensitive gel-forming pentablock copolymers based on commercially available Pluronic (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), PEO-b-PPO-b-PEO) triblock copolymers and cationic diblock copolymers based on poly(ethylene glycol) methyl ether (PEGME) were synthesized by oxyanionic polymerization. Polymerization of the cationic moiety, poly((diethylamino)-ethyl methacrylate), PDEAEM, was initiated by a difunctional potassium alcoholate of the triblock Pluronic copolymer F127 (PEO 106-PPO69-PEO106) or PEGME. The difunctionality of the initiation using the triblock macroinitiator, indicating formation of a pentablock copolymer rather than a tetrablock copolymer, was verified by functionalized termination of the living polymer chains. Critical micellization temperatures (cmt) of the synthesized polymers were obtained from differential scanning calorimetry for the pentablock materials. The pentablock copolymers retained the thermoreversible gel-forming properties of Pluronic F127 as well as similar cmt values. The polydispersity of both the diblock and pentablock copolymers was similar to the macroinitiators, indicating a very low polydispersity associated with the addition of the cationic PDEAEM blocks. Both of the materials show pH-sensitive release behavior, whereas the native polymers do not.

A versatile method for preparing amorphous degradable elastomers with tunable properties that can be easily fabricated into a wide variety of shape-specific devices was investigated. Completely amorphous, liquid poly(ester ether) prepolymers with number-average molecular weights between 4 and 6 x 10(3) g/mol were prepared via condensation polymerization. These liquid prepolymers were then thermally cross-linked to form degradable elastomeric structures. The ability to vary the composition of these liquid prepolymers allows for easy control of the mechanical and degradation properties of the resulting elastomeric structures. Materials can be designed to completely degrade in vitro over a range of 30 days to 6 months, while the Young's modulus can be varied over 3 orders of magnitude (G = 0.02-20 MPa). Also, the liquid nature of these prepolymers makes them amenable to a wide variety of fabrication techniques. Using traditional and modified imprint lithography techniques, we have fabricated devices that demonstrate a wide variety of biologically applicable topologies, which could easily be extended to fabricate devices with more complex geometries. Until now, no method has combined this ease and speed of fabrication with the ability to control the mechanical and degradation properties of the resulting elastomers over such a broad range.

High molecular weight poly(2,5‐benzophenone) derivatives were prepared by Ni(0)‐catalyzed coupling of 4′‐substituted 2,5‐dichlorobenzophenones. Monomers were synthesized by the Friedel–Crafts reaction of 2,5‐dichlorobenzoyl chloride and alkyl‐substituted benzenes in the presence of aluminum chloride. The resulting polymers are soluble and show no evidence of crystallinity by DSC. Number average molecular weights are in the range of 9.2 × 103–11.7 × 103 g/mol by multiple angle laser light scattering (MALLS). Molecular weights obtained by MALLS are only slightly lower (∼90%) than those obtained by GPC (polystyrene standards). These polymers exhibit high thermal stability with glass transition temperatures ranging from 173 to 225°C and weight loss occurring above 450°C in nitrogen and 430°C in air. Additionally, the polymers were blended and the resulting polymer films appear to be miscible by DSC results. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2611–2618, 1998

A versatile method for preparing linear, unsaturated polyesters through condensation polymerization of trans-β-hydromuconic acid (HMA) with a variety of diols using Sn(Oct)2 and Novozyme-435 as catalysts was explored. Poly(1,8-octanediol hydromuconoate) was the highest molecular weight homopolymer prepared with a 〈M n〉 of 10.5 × 103 g/mol and polydispersity of 2.0. These materials showed unique melting behavior that was dependent on the number of carbons in the diol. Melting points ranged from 40 to 70 °C. Copolymers where the amount of HMA was diluted by adipic acid were prepared and had a 〈M n〉 as high as 13.0 × 103 g/mol and polydispersities below 2.0. The double bonds of these materials were chemically modified through epoxidation in yields greater than 93% and with no degradation of the polymer backbone. Materials with hydroxyl end groups were prepared through stoichiometric mismatch. Unsaturated poly(ester ether)s that are amorphous liquids with T g below −40 °C were prepared using diethylene glycol as the diol.

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