Cross-linked polymer microparticles with tunable surface properties by the combination of suspension free radical copolymerization and Click chemistry.

We propose a general, versatile and broad in scope two-steps approach for the elaboration of cross-linked polymer microparticles (µPs) with tunable functionalities and surface properties. Surface-functionalized cross-linked polymer µPs with diameter in the 80 µm range are prepared by the combination of: 1) suspension free radical copolymerization of styrene, propargyl methacrylate and 1,6-hexanediol dimethacrylate, 2) subsequent covalent tethering of a variety of azide-functionalized moieties (i.e. rhodamine B fluorescent dye or poly(ethylene glycol) (PEG) brush precursor) by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) and, 3) optional N-alkylation of the 1,2,3-triazole groups followed by anion exchange reaction to afford covalently-tethered 1,2,3-triazolium ionic liquids with iodide or cresol red counter-anions. The resulting µPs are characterized by laser diffraction, differential scanning calorimetry, as well as by optical, confocal fluorescence, scanning electron and atomic force microscopies. Finally, the rheological properties of concentrated suspensions (volume fractions of 0.40 and 0.44) of the different synthesized µPs dispersed in a 1:1 (vol/vol) mixture of polyalkylene glycol and water are studied. The modification of µPs surface properties contributes not only to change the stability of the suspensions against flocculation, but also to significantly modify their rheological behavior at high shear stresses. This represents a clear experimental evidence of the importance of non-hydrodynamic contact forces in the rheology of non-Brownian suspensions (NBSs).

Facile and Rapid Access to Glyconanocapsules by CuAAC Interfacial Polyaddition in Miniemulsion Conditions.

Glyconanocapsules with a biocompatible oily core have been successfully prepared by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) interfacial step growth polymerization between 6,6'-diazido-6,6'-dideoxysucrose and bis(propargyloxy)butane in oil-in-water miniemulsion conditions. Optimization of the interfacial polymerization process in dispersed medium afforded the rapid and reproducible preparation of stable monodispersed glyconanocapsules having a diameter around 200 nm.

'All-supramolecular' nanocapsules from low-molecular weight ureas through interfacial addition reaction in miniemulsion.

This contribution presents a new strategy for preparing nanocapsules with a shell made of a supramolecular polymer which repeating units are held together by reversible interactions rather than covalent bonds. These nanocapsules were prepared in classical miniemulsion through interfacial addition reaction of a diisocyanate (IPDI) and a monoamine (iBA), forming low-molecular weight bis-ureas moieties which are strong self-complementary interacting molecules through hydrogen-bonding. The nanocapsules present a diameter around 100 nm, and MALDI-TOF MS and (1)H NMR analyses confirm the expected molecular characteristics for the shell. This strategy opens the scope of a new type of nanomaterials exhibiting stimuli-responsiveness due to the reversible interaction linking the repeating units.