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Université de Fribourg

Towards polymers with molecular auxeticity

Alizadeh, Mahshid ; Tennie, Iris K. ; Steiner, Ullrich ; Kilbinger, Andreas F. M.

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 25–28

For many decades, it has been challenging to synthesize auxetic materials at the molecular level. Auxetic materials exhibit counterintuitive behavior; they expand perpendicularly to the direction in which they are stretched. An aromatic macrocycle containing a sequence of N-substituted and N-unsubstituted amides was designed to resemble the re-entrant structure found in macromolecular auxetic...

Université de Fribourg

Synthesis of telechelic poly(p-benzamide)s

Alizadeh, Mahshid ; Kilbinger, Andreas F. M.

In: Macromolecules, 2018, vol. 51, no. 11, p. 4363–4369

Well-defined telechelic poly(benzamide)s were synthesized by chain-growth polycondensation of phenyl-4-amino benzoate and pentafluorophenyl-4-amino benzoate derivatives with a bifunctional initiator in the presence of LiTMP as base. The polymerization was carried out at −70 °C to prevent self-initiated polymerization. To confirm the control over molecular weight, different defined...

Université de Fribourg

Facile synthesis of a high molecular weight amphiphilic aramid–ROMP block copolymer

Badoux, Michael ; Drechsler, Susanne ; Pal, Subhajit ; Kilbinger, Andreas F. M.

In: Macromolecules, 2017, vol. 50, no. 23, p. 9307–9314

Herein we report the facile synthesis of an amphiphilic rod–coil block copolymer obtained by the coupling of an amine-terminated poly(dimethylpropylamine norbornene imide) (PDMAPNI) and a pentafluorophenol ester-terminated poly(dimethoxybenzyl p-aminobenzoate) (PAram). Postpolymerization amide N- deprotection of the block copolymer yielded a strongly aggregating water-soluble rod– coil...

Université de Fribourg

Synthesis of high molecular weight poly(p-benzamide)s

Badoux, Michael ; Kilbinger, Andreas F. M.

In: Macromolecules, 2017, vol. 50, no. 11, p. 4188–4197

The polymerization of aromatic para-amino acid ester derivatives was studied using model compounds. Mechanistic and kinetic experiments led to the discovery of some side reactions. Finally, high molecular weight poly(p-benzamide)s were synthesized and characterized. The use of highly reactive pentafluorophenol ester lead to polymers up to molecular weights of around 50 000 Da....

Université de Fribourg

The influence of substituents on gelation and stacking order of oligoaramid – based supramolecular networks

Drechsler, Susanne ; Balog, Sandor ; Kilbinger, Andreas F. M. ; Casalini, Tommaso

In: Soft Matter, 2019, vol. 15, no. 36, p. 7250–7261

Self-assembly has proven to be a powerful tool for functional, smart materials such as hydrogels derived from low molecular weight compounds. However, the targeted design of functional gelators remains difficult. Here, we present a set of four Y-shaped aromatic amide tetramers with varying functionalities able to undergo different non- covalent interactions. These compounds were explored...

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

Branched polymers via ROMP of termimers

Hanik, Nils ; Kilbinger, Andreas F. M.

In: Macromolecular Rapid Communications, 2016, vol. 37, no. 6, p. 532–538

Today's olefin metathesis catalysts show high reactivity, selectivity, and functional group tolerance and allow the design of new syntheses of precisely functionalized polymers. Here the synthesis of a new end-capping reagent is investigated allowing the introduction of a highly reactive activated ester end-group at the polymer chain end as well as its prefunctionalization to directly...

Université de Fribourg

Controlling molecular self-assembly on an insulating surface by rationally designing an efficient anchor functionality that maintains structural flexibility

Hauke, Christopher M. ; Bechstein, Ralf ; Kittelmann, Markus ; Storz, Christof ; Kilbinger, Andreas F. M. ; Rahe, Philipp ; Kühnle, Angelika

In: ACS Nano, 2013, vol. 7, no. 6, p. 5491–5498

Molecular self-assembly on surfaces is dictated by the delicate balance between intermolecular and molecule–surface interactions. For many insulating surfaces, however, the molecule–surface interactions are weak and rather unspecific. Enhancing these interactions, on the other hand, often puts a severe limit on the achievable structural variety. To grasp the full potential of molecular...

Université de Fribourg

Polyvinyl alcohol as a biocompatible alternative for the passivation of gold nanorods

Kinnear, Calum ; Burnand, David ; Clift, Martin J. D. ; Kilbinger, Andreas F. M. ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Angewandte Chemie International Edition, 2014, vol. 53, no. 46, p. 12613–12617

The functionalization of gold nanorods (GNRs) with polymers is essential for both their colloidal stability and biocompatibility. However, a bilayer of the toxic cationic surfactant cetyl trimethylammonium bromide (CTAB) adsorbed on the nanorods complicates this process. Herein, we report on a strategy for the biocompatible functionalization of GNRs with a hydrophobic polymeric precursor,...

Université de Fribourg

Synthesis and properties of poly(norbornene)s with lateral aramid groups

Kong, Phally ; Drechsler, Susanne ; Balog, Sandor ; Schrettl, Stephen ; Weder, Christoph ; Kilbinger, Andreas F. M.

In: Polymer Chemistry, 2019, vol. 10, no. 16, p. 2057–2063

This paper deals with the synthesis and investigation of comb-like poly(norbornene)s carrying lateral rod-like aramid groups. Two types of norbornene-based monomers were synthesized and copolymerized with a norbornene carrying an aliphatic side chain using ring opening metathesis polymerization (ROMP). The new monomers contain aramid derivatives that display different types of non-covalent...