In the present study, scanning electrochemical microscope (SECM) was used to investigate the transport properties of these membranes in more details. The results show that the PDMAEMA content controls the permeability of the membrane but also, a surprising time-dependent behaviour was observed: the permeability of the PDMAEMA:CA membranes decreased as a function of time and ellipsometer results showed that this behaviour is not related to the swelling of the membrane. Instead, the time-dependent behaviour might be an indicator of the conformational change of PDMAEMA molecules – either due to the screening of charges or change in degree of ionisation - blocking the membrane pores and this results in a change in permeability as a function of time. A material with such a time-dependent behaviour is an extremely interesting candidate when designing smart and responsive coatings and membranes for temporal biomedical implants.
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