One-Step Fabrication of pH-Responsive Membranes and Microcapsules through Interfacial H-Bond Polymer Complexation

TL;DR

This paper introduces a simple, one-step method to create pH-responsive, biocompatible microcapsules with self-healing properties using interfacial hydrogen bond complexation, suitable for scalable production in various fields.

Contribution

It presents a novel one-step fabrication process for pH-responsive microcapsules via interfacial hydrogen bonding, enabling scalable and versatile production of functional capsules.

Findings

Capsules exhibit self-healing and pH-responsive behavior.

Process allows production from micro-scale to centimeter-scale.

Membranes dissolve at pH > 6, releasing contents.

Abstract

Biocompatible microencapsulation is of widespread interest for the targeted delivery of active species in fields such as pharmaceuticals, cosmetics and agro-chemistry. Capsules obtained by the self-assembly of polymers at interfaces enable the combination of responsiveness to stimuli, biocompatibility and scaled up production. Here, we present a one-step method to produce in situ membranes at oil-water interfaces, based on the hydrogen bond complexation of polymers between H-bond acceptor and donor in the oil and aqueous phases, respectively. This robust process is realized through different methods, to obtain capsules of various sizes, from the micrometer scale using microfluidics or rotor-stator emulsification up to the centimeter scale using drop dripping. The polymer layer exhibits unique self-healing and pH-responsive properties. The membrane is viscoelastic at pH = 3, softens as pH is progressively raised, and eventually dissolves above pH = 6 to release the oil phase. This one-step method of preparation paves the way to the production of large quantities of functional capsules.