Novel Biodegradable Adaptive Hydrogels: Controlled Synthesis and Full Characterization of the Amphiphilic Co‐Networks

Abstract

Adaptive and amphiphilic poly(N,N-dimethylamino-2-ethyl methacrylate-graft-poly[epsilon-caprolactone]) co-networks (netP(DMAEMA-g-PCL)) were synthesized from a combination of controlled polymerization techniques. Firstly, PCL cross-linkers were produced by ring-opening polymerization (ROP) of epsilon-CL initiated by 1,4-butane-diol and catalyzed by tin(II) 2-ethylhexanoate ([Sn(Oct)2]), followed by the quantitative esterification reaction of terminal hydroxyl end-groups with methacrylic anhydride. Then, PCL cross-linkers were copolymerized to DMAEMA monomers by atom-transfer radical polymerization (ATRP) in THF at 60 degrees C using CuBr complexed by 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) and 2-ethyl isobutyrylbromide (EiBBr) as catalytic complex and initiator, respectively. A comprehensive study of gel formation was carried out by employing dynamic light scattering (DLS) to determine the gel point as a function of several parameters and to characterize the viscous solutions obtained before the gel point was reached. The evolution of the mean diameters was compared to a model previously developed by Fukuda and these attest to the living formation of the polymer co-network. Furthermore, we also demonstrated the reliability of ATRP for producing well-defined and homogeneous polymer co-networks by the smaller deviation from Flory's theory in terms of cross-linking density. For sake of clarity, the impact of polymerization techniques over the final structure and, therefore, properties was highlighted by comparing two samples of similar composition, but that were produced by either ATRP or thermal-initiated free-radical polymerization (FRP).

Radical Ring-Opening Polymerization: Scope, Limitations, and Application to (Bio)Degradable Materials

“…When the polymerization in the presence of a crosslinker goes beyond the gel point, cross-linked 3D polymeric networks are obtained. A representative illustration of this approach is the design of degradable (hydro)gels, by either FRP [400][401][402] or RDRP. 346,400,[403][404][405][406] RDRP techniques generally provided more homogeneous structures and degradation products compared to those obtained by FRP.…”

Development of a Library of N‐Substituted Maleimides for the Local Functionalization of Linear Polymer Chains

“…Nowadays, complex architectures, such as block copolymers, graft copolymers, stars, miktoarm stars, macrocycles and macromolecular brushes, can be routinely synthesized via a variety of synthetic routes. [4,5] On the other hand, relatively little work have been done for controlling the microstructure (i.e., tacticity and monomer sequences) of synthetic polymers, even though this aspect is of particular scientific relevance. For example, polymers with controlled microstructures play a key role in nature.…”

Broad-Spectrum Antimicrobial Polycarbonate Hydrogels with Fast Degradability

“…It is worth mentioning, although they were using highly acidic conditions (dioxane/aqueous HCL mixture (85:15)), only partial degradation was observed 48. …”