Layer-by-layer assembled microgels can combine conflicting properties: Switchable stiffness and wettability without affecting permeability.

MAZA, ELIANA; VON BILDERLING, CATALINA; CORTEZ, M. LORENA; DÍAZ, GISELA; BIANCHI, MICAELA; PIETRASANTA, LÍA ISABEL; GIUSSI, JUAN MARTÍN; AZZARONI, OMAR

LANGMUIR

AMER CHEMICAL SOC

Año: 2018

0743-7463

Responsive interfacial architectures of practical interest commonly require the combination of conflicting properties in terms of their demand upon material structure. Switchable stiffness, wettability and permeability, key features for tissue engineering applications, are in fact known to be exclusively interdependent. Here we present a nanoarchitectonic approach that decouples these divergent properties by the use thermo-responsive microgels as building blocks for the construction of three-dimensional arrays of interconnected pores. Layer-by-layer assembled poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-PMAA) microgel films were found to exhibit an increase in hydrophobicity, stiffness and adhesion properties upon switching the temperature from below to above the lower critical solution temperature, while the permeability of redox probes through the film remained unchanged. Our findings indicate that the switch in hydrophilicity and nanomechanical properties undergone by the microgels does not compromise the porosity of the film, thus allowing the free diffusion of redox probes through the polymer-free volume of the submicrometer pores. This novel approach for decoupling conflicting properties provides a strategic route for creating tailorable scaffolds with unforeseen functionalities.