Monitoring a polycycloaddition by the combination of dynamic rheology and FTIR spectroscopy

Contribution of Dynamic Rheology Coupled to FTIR and Raman Spectroscopies to the Real-Time Shaping Ability of a Hyperbranched Polycarbosilane

In the field of non-oxide ceramics, the polymer-derived ceramic (PDC) approach appears to be very promising, especially for obtaining easily shaped and homogeneous materials in terms of structure and composition. However, in order to reach a suitable form during the process, it is often necessary to study the rheology of preceramic polymers while they are modified during polymerisation or crosslinking reactions. Given this need in the understanding of the real-time rheology of macromolecules during their synthesis, a rheometer coupled with both an infrared spectrometer and a Raman probe is described as a powerful tool for monitoring in situ synthesised polycarbosilanes. Indeed, this original device allows one to control the viscosity of a hyberbranched polycarbosilane from defined difunctional and tetrafunctional monomers. Meanwhile, it links this evolution to structural modifications in the macromolecular structure (molar masses, dispersity and conformation), based on SEC-MALS analyses, synchronised by the monomer conversion determined by using Raman and infrared spectroscopies, a common denominator of the aforementioned instrumental platform.

A Bio-inspired Multifunctionalized Silk Fibroin

A bio-inspired multifunctionalized silk fibroin (BMS) was synthesized in order to mimic the interaction of nidogen with the type IV collagen and laminin of basement membranes. The designed BMS consists of a motif of laminin α-chain-derived, called IK peptide, and type IV collagen covalently bound to the silk fibroin (SF) by using EDC/NHS coupling and a Cu-free click chemistry reaction, respectively. Silk fibroin was chosen as the main component of the BMS because it is versatile and biocompatible, induces an in vivo favorable bioresponse, and moreover can be functionalized with different methods. The chemical structure of BMS was analyzed by using X-ray photoelectron spectroscopy, attenuated total reflection-Fourier transform infrared, cross-polarization magic angle spinning nuclear magnetic resonance techniques, and colorimetric assay. The SF and BMS solutions were cross-linked by sonication to form hydrogels or casted to make films in order to evaluate and compare the early adhesion and viability of MRC5 cells. BMS hydrogels were also characterized by rheological and thermal analyses.

Quantitatively monitoring polymer chain growth and topology formation based on monodisperse polymers

In this work, a novel technique for monitoring polymer chain growth and topology formation was demonstrated by precision synthesis of monodisperse polymers, which opened a novel avenue for obtaining real-time polymer structure information.