Facile bio-functionalized design of thermally responsive molecularly imprinted composite membrane for temperature-dependent recognition and separation applications

It is becoming significant needed that ‘smart membranes’ with specific recognition sites can rapidly change flow rates in response to external stimuli. Herein, inspired by a mussel-inspired two-step surface synthesis methodology, we have reported a novel system for harvesting thermally responsive molecularly imprinted composite membranes (TMICMs) with excellent selective adsorption and separation performance toward template molecules. A self-polymerized polydopamine coating process was initially conducted to obtain the highly adjustable active surfaces. The TMICMs were then prepared through an in situ photoinitiated ATRP method by using N-isopropylacrylamide (NIPAm) as the thermo-responsive backbone monomer. Attributing to the formation of the polydopamine coating surfaces, remarkably enhanced rebinding capacity (2.343 mmol cm⁻²) was obtained. Importantly, the as-prepared TMICMs with thermo-responsive “specific recognition sites” also exhibited excellent temperature-dependent switching modes for selective recognition and separation of the template molecule (ciprofloxacin). Meanwhile, this bioinspired thermo-responsive method could not only present an outstanding permselectivity property (separation factor β was more than 4.0), but also showed excellent structural stability and adsorption regeneration performance (the TMICMs could still possessed 92.74% of the maximum adsorption capacity after four adsorption/desorption cycles). Finally, we envision that the developed bio-adhesive platform synthesis strategy employed in this case can be utilized in a broad range of applications and will have a great impact on the fields of fluid handling, thermo-responsive sensors, membrane-based drug delivery and separation.