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Université de Fribourg

Bis-TEGylated poly(p-benzamide)s: combining organosolubility with shape persistence

Schulze, Maren ; Michen, Benjamin ; Fink, Alke ; Kilbinger, and Andreas F. M.

In: Macromolecules, 2013, vol. 46, no. 14, p. 5520–5530

The synthesis of perfectly planar, bis-substituted aromatic polyamides is reported herein. With highly flexible triethylene glycol chains attached and conformational restriction through intramolecular, bifurcated hydrogen bonds these are among the most shape-persistent yet organo-soluble polymers to date. Starting from 4-nitrosalicylic acid, our group developed a route to phenyl-2,5-bis-TEGylated...

Université de Fribourg

Nanoparticles and cells: an interdisciplinary approach

Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: Chimia, 2012, vol. 66, no. 3, p. 104-109

In this article we present an overview of some of our research in the field of nanoscience. By combining two different scientific backgrounds (chemistry and biology), we investigate nanoparticle-cell interactions from different angles. This requires an interdisciplinary approach involving material synthesis and characterization, cell biology (biochemistry) and microscopy. In particular, we...

Université de Fribourg

Tuning the solubility of hepta(p-benzamide)s via the monomer sequence

Seyler, Helga ; Kilbinger, Andreas

In: Tetrahedron Letters, 2012, p. -

The automated synthesis of hepta(p-benzamide) hetero sequences on solid support using a modified peptide synthesizer is reported. The oligomers are synthesized from 4-aminobenzoic acid and 4-amino-2-(hexyloxy)benzoic acid, the latter carrying a solubilizing hexyl side chain. It is known from previous studies that both the unsubstituted hepta(p-benzamide) and the fully hexyloxy-substituted...

Université de Fribourg

ROMP copolymers for orthogonal click functionalizations

Schaefer, Mark ; Hanik, Nils ; Kilbinger, Andreas F. M.

In: Macromolecules, 2012, p. -

The ring-opening metathesis polymerization using ruthenium carbene initiators developed by Grubbs et al. is one of the most functional group tolerant living polymerization methods known. One of the most used postpolymerization functionalization methods used today is the copper-catalyzed 1,3-dipolar cycloaddition between alkynes and organic azides. Organic azides are, however, not tolerated by...

Université de Fribourg

Ab-initio crystal structure analysis and refinement approaches of oligo p-benzamides based on electron diffraction data

Gorelik, Tatiana E. ; Streek, Jacco van de ; Kilbinger, Andreas F. M. ; Brunklaus, Gunther ; Kolb, Ute

In: Acta Crystallographica Section B, 2012, vol. 68, no. 2, p. 171-181

Ab-initio crystal structure analysis of organic materials from electron diffraction data is presented. The data were collected using the automated electron diffraction tomography (ADT) technique. The structure solution and refinement route is first validated on the basis of the known crystal structure of tri-p-benzamide. The same procedure is then applied to solve the previously unknown crystal...

Université de Fribourg

Biologically inspired hierarchical design of nanocomposites based on poly(ethylene oxide) and cellulose nanofibers

Changsarn, Sutheerat ; Mendez, James D. ; Shanmuganathan, Kadhiravan ; Foster, E. Johan ; Weder, Christoph ; Supaphol, Pitt

In: Macromolecular Rapid Communications, 2011, vol. 32, no. 17, p. 1367–1372

Attempts to create hierarchically structured, uniaxially oriented nanocomposites comprising cellulose nanowhiskers (CNWs), which promise anisotropic mechanical properties, are exceedingly rare. We report here the fabrication of uniaxially-oriented arrays of microfibers based on poly(ethylene oxide) (PEO) and CNWs by electrospinning. Compared with the neat PEO fibers, the incorporation of CNWs...

Université de Fribourg

Magnetic properties of silica coated spindle-type hematite particles

Reufer, Mathias ; Dietsch, Hervé ; Gasser, Urs ; Grobéty, Bernard ; Hirt, A. M. ; Malik, Vivek Kumar ; Schurtenberger, Peter

In: Journal of Physics: Condensed Matter, 2011, vol. 23, no. 6, p. 065102

Magnetic properties of particles are generally determined from randomly oriented ensembles and the influence of the particle orientation on the magnetic response is neglected. Here, we report on the magnetic characterization of anisotropic spindle- type hematite particles. The easy axis of magnetization is within the basal plane of hematite, which is oriented perpendicular to the spindle axis....

Université de Fribourg

Synthesis, electrical properties, and nanocomposites of poly(3,4-ethylenedioxythiophene) nanorods

Mendez, James D. ; Weder, Christoph

In: Polymer Chemistry, 2010, vol. 1, no. 8, p. 1237-1244

Cellulose nanofibers or “whiskers” derived from tunicates were coated with PEDOT:PSS to produce high-aspect-ratio nanorods with high electrical conductivity. Films made from these PEDOT:PSS whiskers have surface resistivities as low as 97 Ω/□. The nanorods were found to disperse well in polar organic solvents such as dimethylformamide, which allowed the fabrication of nanocomposites with...

Université de Fribourg

Thermoresponsive hybrid microgel particles with intrinsic optical and magnetic anisotropy

Dagallier, Camille ; Dietsch, Hervé ; Schurtenberger, Peter ; Scheffold, Frank

In: Soft Matter, 2010, vol. 6, p. 2174-2177

We describe the synthesis of thermoresponsive, magnetic, optically anisotropic and orientable colloidal particles based on poly(N-isopropylacrylamide) hybrid microgels (PNIPAMs) with an embedded ellipsoidal hematite (α-Fe₂O₃) core. Our ability to orient the particles with a magnetic field is demonstrated by small angle X-ray scattering and by optical polarization microscopy.

Université de Fribourg

Synthesis and self-assembly behavior of poly(fluorenylstyrene)-block-poly(2-vinylpyridine) block copolymers and their blends with single wall carbon nanotubes (SWCNTs)

Li, Chaoxu ; Hsu, Jung-Ching ; Sugiyama, Kenji ; Hirao, Akira ; Chen, Wen-Chang ; Mezzenga, Raffaele

In: Macromolecules, 2009, vol. 42, no. 15, p. 5793–5801

We have synthesized a series of poly[4-(9,9-dihexylfluoren-2-yl)styrene]-block-poly(2-vinylpyridine) (P(St-F1)-b-P2VP) and poly[4-di(9,9-dihexylfluoren-2-yl)styrene]-block-poly(2-vinylpyridine) (P(St-F1₂)-b-P2VP) comblike block copolymers and investigated their self-assembly behavior. The block composition, molecular weight, and the length of the fluorene side chain...