Instant strong and responsive underwater adhesion is significant for many biomedical, industrial, and household applications. However, underwater adhesives simultaneously possessing these advantages are challenging to fabricate because strong and responsive adhesions are usually opposing properties. Herein, we have prepared bioinspired supramolecular polymeric adhesives containing complementary nucleobase moieties in nucleic acids and have demonstrated instantaneous underwater adhesion with an adhesion strength reaching as high as 1.5 MPa. Strong underwater adhesion is attributed to the high capability of the adhesives to substantially remove the interfacial water, which can be further modulated by temperature, light, and pH. Excellent underwater adhesion performances have been achieved on various substrates and under distinct aqueous conditions, showcasing the wide applications of the bioinspired nucleobase-containing adhesives developed here. This work opens up a new opportunity for fabricating underwater adhesives for diverse applications with the combined advantages of instant strong and responsive adhesion.

In this work, we have investigated a pH-modulated complexation between two oppositely charged strong polyelectrolytes to demonstrate the effect of counterion-mediated hydrogen bonding (CMHB) on polyelectrolyte complexation. We have found that such a pH-modulated complexation cannot be understood without considering the CMHB. Thermodynamically, the effect of CMHB on the polyelectrolyte complexation is manifested by the alteration of both enthalpic and entropic contributions to the free energy change. The pH-dependent intrinsic ion-pairing and complex coacervation processes of the polyelectrolyte complexation can be understood when considering the CMHB. Our study demonstrates that both the extent of polyelectrolyte complex formation in bulk solutions and the formation of polyelectrolyte multilayers on surfaces are controlled by the pH-dependent intrinsic ion-pairing process. Furthermore, on the basis of the pH-dependent intrinsic ion pairing, the properties of the multilayers can be tuned by pH. This work provides a new strategy to control the polyelectrolyte complexation with counterions and will inspire new ideas for building advanced polyelectrolyte materials.

Surface force measurements have revealed that at very high electrolyte concentrations as well as in neat and diluted ionic liquids and deep eutectic solvents, the range of electrostatic interactions is far greater than the Debye length. Here, we explore the consequences of this underscreening for soft-matter and colloidal systems by investigating the stability of nanoparticle dispersions, the self-assembly of ionic surfactants, and the thickness of soap films. In each case, we find clear evidence of re-entrant properties due to underscreening at high salt concentrations. Our results show that underscreening in concentrated electrolytes is a general phenomenon and is not dependent on confinement by macroscopic surfaces. The stability of systems at very high salinity due to underscreening may be beneficially applied to processes that currently use low-salinity water.

Gel polymer electrolyte (GPE)-based quasi-solid-state supercapacitors (QSSCs) have attracted great interest in the last 10 years due to the increasing demand of wearable electronics. However, the strong dependence of electrochemical performances on the electrode thickness of the GPE-based QSSCs severely limits their applications. Herein, a low-molecular-weight supramolecular gel electrolyte (SGE) has been successfully developed to render the SGE-based QSSCs a comparable dependence of electrochemical performances on electrode thickness to those based on bulk electrolyte solutions. Two main reasons are responsible for such an observation. First, the as-prepared SGE has an ionic conductivity as high as ∼421 mS cm–1. Second, the combined advantages of small molecular size, low solution viscosity, and good wettability endow the SGE with a capability to effectively infill the thick porous activated carbon electrodes through a sol–gel transition method. Moreover, it has also been demonstrated that the SGE developed here is applicable to a wide range of QSSCs.

A polyzwitterion, salt mixture, and organic solvent layer not only play respective roles in, but also exhibit a cooperative effect on the performance of supercapacitors.