Amphiphilic Polymer Conetworks Based on End Group Cross-Linked Poly(2-oxazoline) Homo- and Triblock Copolymers

Abstract

Novel amphiphilic polymer conetworks (APCNs) were prepared via end group cross-linking. To this end, poly(2-methyloxazoline) (PMOx), poly(2-butyloxazoline) (PBuOx), and the triblock copolymers PMOx-b-PBuOx-b-PMOx were synthesized by cationic ring-opening polymerization in varying block lengths and telechelically modified with N,N -bis(2-aminoethyl)ethylendiamine (TREN). First the cross-linking with 1,4-dibromo-2-butene (DBB) was established for the homopolymers. The swelling of those matches the theoretical value for full cross-linking, indicating that in this way “near perfect” networks could be obtained. Mixtures of the homopolymers and the triblock copolymers were cross-linked with DBB to give APCNs with similar polymer segments but different network topology. AFM showed that all formed APCNs are nanophase separated with slight structural differences in the nanostructures when comparing conetworks with similar composition but different cross-linking strategies. The more drastic difference between APCNs of different topologies was found in their swelling characteristics, which clearly proves the influence of conetwork structure on their properties.

Self‐Sealing and Puncture Resistant Breathable Membranes for Water‐Evaporation Applications

“…The plant Aristolochia macrophylla , a North American liana, has a mechanism to mechanically close defects. The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized. Inspired by this phenomenon, Speck and co-workers developed an airtight pneumatic membrane (as used, e.g., in infl atable boats) that is capable to close punctures by the expansion of a polyurethane-foam.…”

“…The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized. The self-sealing membrane consisted of a waterproof and breathable, non-porous poly(ether ester) multi-block copolymer membrane (PEE; Sympatex membrane) [ 2,22 ] onto which an amphiphilic polymer co-network (APCN) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] was polymerized.…”

Investigation of the swelling behavior of hydrogels derived from high‐molecular‐weight poly(2‐ethyl‐2‐oxazoline)

“…However, POx‐based hydrogels have been found to show no sharp phase transition, but to transit from a highly to a lowly swollen state due to a change of the swelling–deswelling rate d S /d T over a broad temperature range . Such POx‐hydrogels are prepared by end‐group linking, simultaneous copolymerization of a monomer with a multifunctional cross‐linker, or only using a radical starter and a multifunctional cross‐linker …”

Synthesis of well‐defined star‐shaped poly(ε‐caprolactone)/poly(ethylbene glycol) amphiphilic conetworks by combination of ring opening polymerization and “click” chemistry

“…Under normal situation, APCNs were achieved by free radical polymerization, controlled radical polymerization, and the chemical combination of hydrophilic and hydrophobic prepolymers, which has been implemented by dissolving hydrophilic and hydrophobic prepolymers in common good solvents, and combining them by crosslinking to networks. However, by these synthetic methods, ill‐defined APCNs network structure with defective or disordered molecular structure was synthesized, the main reason was low monomer conversion rate as well as different reactivity of macromonomer and micromolecule.…”