Double Hydrophilic Poly(ethylene oxide)‐block‐Poly(dehydroalanine) Block Copolymers: Comparison of Two Different Synthetic Routes

Abstract

Two different synthetic pathways give access to the amphiphilic block copolymer poly(ethylene oxide)‐block‐poly(tert‐butoxycarbonylaminomethylacrylate). In the first approach, two end‐functionalized segments are linked via click chemistry; and in the second approach, a poly(ethylene oxide) (PEO) based macroinitiator is chain extended via atom transfer radical polymerization (ATRP). In both cases the linking unit consists of an amide group, which is necessary to effectively deprotect the corresponding polymer precursor without cleavage of both segments. For this, amide‐containing ATRP initiators are employed and successful synthesis by nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC) analyses before comparing both pathways is demonstrated. After deprotection, a novel double hydrophilic block copolymer, poly(ethylene oxide)‐block‐poly(dehydroalanine), is obtained, which is investigated using SEC (aqueous and DMSO) and 1H‐NMR spectroscopy. Containing a potentially zwitterionic PDha segment and a high density of both amino and carboxylic groups, pH‐dependent aggregation of the block copolymer is expected and is studied using dynamic light scattering, revealing interesting solution properties. The corresponding polymers are applied in various areas including drug delivery systems or in biomineralization.

Triple‐Responsive Polyampholytic Graft Copolymers as Smart Sensors with Varying Output

“…Poly(dehydroalanine) (PDha), a polyampholyte featuring high charge density and both amine and carboxylate moieties in every repeat unit, [ 28 ] was introduced recently as a versatile platform to obtain tailor‐made copolymers with defined hydrophilicity, [ 29,30 ] as a building block in double hydrophilic block copolymers, [ 31 ] or as a template for the pH‐controlled formation of Au/Ag alloy nanoparticles. [ 32 ] Hereby, the polyampholytic PDha backbone offers pH‐dependent net charge and a high density of functional groups as anchoring points for grafts or as binding sites for metal ions.…”

“…[ 32 ] Hereby, the polyampholytic PDha backbone offers pH‐dependent net charge and a high density of functional groups as anchoring points for grafts or as binding sites for metal ions. [ 31,32 ] We now introduce thermoresponsive PDha‐based graft copolymers by grafting one single NIPAAm unit. While PNIPAAm is probably the most studied LCST polymer overall, [ 33 ] this effect has so far not been shown for short side chains.…”

Polyelectrolyte Functionalisation of Track Etched Membranes: Towards Charge-Tuneable Adsorber Materials

“…The targeted porous adsorber membranes could yet be accessible, for example by using alkylazide-functionalized polyethersulfone base membranes in combination with alkyne terminated PtBAMA via the Huisgen addition as a “click” reaction. Both parts of this approach have already been performed successfully, albeit not yet in this specific combination [ 34 , 35 ].…”

Playing construction with the monomer toy box for the synthesis of multi‐stimuli responsive copolymers by reversible deactivation radical polymerization protocols

“…ARGET ATRP polymerization of a disulfide‐containing co‐monomer with a vinylether initiator was employed to obtain a temperature/pH/reduction responsive copolymer 74 . The ATRP‐challenging monomer terz ‐butoxycarbonylaminomethyl acrylate ( t BAMA), which forms copper complexes, was copolymerized with a careful optimization of reaction conditions, yielding a precursor to pH‐ and Cu‐ sensitive self‐assembling double hydrophilic block copolymer 75 . Since ATRP initiators consist of aliphatic halides, various architectures for stimuli‐responsive materials become accessible through the structure of ATRP initiators.…”