Sangsik Kima,1, Jun Huangb,1, Yongjin Leec,d, Sandipan Duttac, Hee Young Yooe, Young Mee Jungf, YongSeok Jhoc,d,2, Hongbo Zengb,2, and Dong Soo Hwanga,e,2
aSchool of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea;
bDepartment of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 2V4, Canada;
cAsia Pacific Center for Theoretical Physics, Pohang 790-784, Republic of Korea;
dDepartment of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea;
eDivision of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea;
fDepartment of Chemistry, Kangwon National University, Chunchon 200-701, Republic of Korea
Abstract
It is well known that polyelectrolyte complexes and coacervates can form on mixing oppositely charged polyelectrolytes in aqueous solutions, due to mainly electrostatic attraction between the oppositely charged polymers. Here, we report the first (to the best of our knowledge) complexation and coacervation of two positively charged polyelectrolytes, which provides a new paradigm for engineering strong, self-healing interactions between polyelectrolytes underwater and a new marine mussel-inspired underwater adhesion mechanism. Unlike the conventional complex coacervate, the like-charged coacervate is aggregated by strong short-range cation-π interactions by overcoming repulsive electrostatic interactions. The resultant phase of the like-charged coacervate comprises a thin and fragile polyelectrolyte framework and round and regular pores, implying a strong electrostatic correlation among the polyelectrolyte frameworks. The like-charged coacervate possesses a very low interfacial tension, which enables this highly positively charged coacervate to be applied to capture, carry, or encapsulate anionic biomolecules and particles with a broad range of applications.
polyelectrolyte complexes, complex coacervates, cation-π interaction, like-charged coacervate, surface forces apparatus
1S.K. and J.H. contributed equally to this work.
2To whom correspondence may be addressed.
Author contributions: Y.J., H.Z., and D.S.H. designed research; S.K., J.H., Y.L., S.D., Y.M.J., Y.J., and H.Z. performed research; H.Y.Y., Y.M.J., Y.J., H.Z., and D.S.H. analyzed data; and S.K., J.H., H.Y.Y., Y.M.J., Y.J., H.Z., and D.S.H. wrote the paper.