Synthesis, thiol-yne "click" photopolymerization, and physical properties of networks derived from novel multifunctional alkynes

Multifunctional alkynes (2, 3, or 4 ynes per monomer) were prepared utilizing the nucleophile-catalyzed thio-Michael addition reaction from commercially available multifunctional thiols (2, 3, or 4 thiols) and propargyl acrylate. Real-time FTIR (RTIR) and NMR spectroscopies indicate that the conjugate addition under these conditions proceeds to high conversions within seconds using the nucleophilic catalyst dimethylphenylphosphine, in the absence of solvent, at ambient temperature, and with no side products. A family of polymer networks was prepared by the photoinitiated thiol-yne reaction employing a 2:1 ratio of thiol to alkyne, which resulted in uniformly cross-linked materials of systematically increasing cross-link density. Photopolymerization kinetic profiles indicate that the thiol-yne reaction proceeded rapidly to high conversion with conversions decreasing with increasing functionality of the thiol and/or alkyne groups. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) results clearly indicate that the glass transition temperature increases as the overall cross-link density increases (from -10 to 42 °C by DMTA). An increase in the rubbery modulus (from 6 to 23 MPa at 70 °C) results as the functionality increases, with a concomitant decrease in the molecular weight between cross-links. © 2010 American Chemical Society

Synthesis and applications of biomedical and pharmaceutical polymers via click chemistry methodologies

In this review, the synthesis and application of biomedical and pharmaceutical polymers synthesized via the copper(I)-catalyzed alkyne-azide cycloaddition, the thiol−ene reaction, or a combination of both click reactions are discussed. Since the introduction of both “click” methods, numerous articles have disclosed new approaches for the synthesis of polymers with different architectures, e.g., block and graft copolymers, dendrimers, and hydrogels, for pharmaceutical and biomedical applications. By describing selected examples, an overview is given of the possibilities and limitations that these two “click” methods may offer

Biomimetic block copolymer membranes

Amphiphilic block copolymer membranes, classified as vesicles, are nano-aggregates receiving a lot of scientific interest due to their wide range of potential applications extending from biomedicine (e.g., drug delivery, imaging, nanoreactors) to material science (biosensors, electronics). This chapter summarizes the principles of vesicle formation, various membrane-forming copolymer systems and their properties as well as common techniques for vesicle preparation and characterization. Copolymer membranes with responsiveness to external stimuli are particularly attractive for use in drug delivery and are, therefore, also discussed. In addition, the chapter reviews recent examples of vesicles encapsulating proteins, enzymes and therapeutics as prospective systems for bio-applications

Biohybrid Polymer Capsules

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