A joint research team from the University of Vienna and the University of Edinburgh has recently developed a smart polymer material that responds to pH changes. The achievement was published in Physical Review Letters. The study reveals how controllable conformational changes in polymer molecules can be achieved through charge regulation.

Using computer simulations and theoretical analysis, the team discovered that cyclic polymers undergo a conformational transition from toroidal to twisted shapes when charge is altered. "By adjusting local charge, we can precisely control the overall shape of the molecule," said first author Roman Staňo. When pH changes, polymer monomer units gain or lose charge, triggering reversible reconfiguration of the molecular structure.

The material exhibits unique phase-separation behavior: under specific conditions, regions rich in twisted and toroidal conformations coexist within the same polymer. Professor Christos Likos from the University of Vienna noted: "This gradual and controllable transition from compact to extended states occurs without altering the molecular topology."

The researchers predict that novel synthetic materials based on DNA could exhibit similar behavior. This responsive material holds promise for applications in microfluidic devices, where localized chemical conditions could trigger controllable shape changes and flow regulation.