Shape memory of hydrogen-bonded polymer network/poly(ethylene glycol) complexes

Because of a large difference in storage modulus below and above the glass transition temperature, poly(acrylic acid-co-methyl methacrylate)/poly(ethylene glycol) (P(AA-co-MMA)/PEG) complexes show shape memory properties with a recovery ratio of nearly reach 99%. Before the shape memory testing, it was necessary to determine the conformational changes of the P(AA-co-MMA) gel induced by complexation with linear PEG. It was found that both the concentration and molecular weight of PEG have a strong effect on the complexation with P(AA-co-MMA) gel. In such a system the minimum molecular weight of PEG required for the complex formation lowers to 1000.