Chiral pH-Responsive Amphiphilic Polymer Co-networks: Preparation, Chiral Recognition, and Release Abilities

Novel amphiphilic polymer co-networks (APCNs), poly(N-acryloyl-L-alanine)-l-polydimethylsiloxane (denoted as PNAA-l-PDMS), are prepared, and exhibit remarkable pH-responsiveness, chiral-recognition, and enantioselective-release abilities. The APCNs are prepared by free-radical copolymerization starting from N-acryloyl-L-alanine (NAA) and methacrylate-terminated poly(dimethylsiloxane) (M-PDMS) as co-(macro)monomers. The APCNs show pronounced pH-sensitivity, evidenced by a reversible swelling-deswelling transition upon a cyclicly altering pH. The chiral co-networks are applied for enantioselective recognition and release. A maximum adsorption is achieved towards D-proline (61%), whereas for L-proline, it is only 10%. More interestingly, the release for the L-proline is 90%, whereas for the D-proline, only 70% is released.