pH Stability of Poly(urethane/urea) Capsules Synthesized from Different Hydrophilic Monomers via Interfacial Polyaddition in the Inverse Miniemulsion Process

Abstract

Poly(urethane/urea) capsules with different hydrophilic monomers and toluene-2,4-diisocyanate were prepared using a polyaddition reaction in inverse miniemulsion. The morphology and the size distribution of the prepared capsules were studied via transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS). Furthermore, the capsules were transferred into an aqueous surfactant containing solution and exposed to different pH values (2.5, 7 and 9). The changes in the capsule's shell stability were studied by measuring the amount of a released dye, which had previously been encapsulated, using fluorescence spectroscopy. The specific surface area of nanocapsules was calculated from nitrogen sorption measurements (Brunauer-Emmett-Teller (BET)).

Polymer Micro‐ and Nanocapsules as Biological Carriers with Multifunctional Properties

“…The pH‐responsive permeability of different poly(urethane/urea) nanocapsules synthesized via interfacial polyaddition using various hydrophilic monomers and 2,4‐toluene diisocyanate as a cross‐linker was reported by Baier et al Dual (pH‐ and thermo‐) responsive nanocapsules were successfully synthesized via an inverse miniemulsion copolymerization of N ‐isopropyl acrylamide, N , N ′‐methylene bisacrylamide, and a functional monomer, 4‐vinyl pyridine …”

“…Polyurethane nanocapsules loaded with ibuprofen were synthesized using Miglyol 812 (triglyceride oil) as organic dispersed phase . Polyurethane and polyurea nanocapsules with an aqueous core were successfully formulated performing the interfacial polyaddition/polycondensation reactions in an inverse miniemulsion system . In this case, the cross‐linker is a hydrophobic diisocyanate, which is drop‐wisely added to the aqueous miniemulsion droplets consisting of hydrophilic reagent with more than one hydroxyl or amine groups (Figure ).…”

Future manufacturing and remanufacturing of polymeric materials

“…Miniemulsion polymerization also has the potential to enable totally new products. Latex products such as polyurethanes polyamides, and other step growth monomers have been reported.…”

Preparation of Poly(ethylene glycol)@Polyurea Microcapsules Using Oil/Oil Emulsions and Their Application as Microreactors

“…This process is based on a polycondensation reaction between two highly reactive monomers; it takes place at the boundary of two immiscible phases, and each phase contains one of the two monomers. Polyurea (PU) is the most common polymer prepared via IFP for the synthesis of MCs; it has been thoroughly investigated and applied in different fields [ 57 , 58 , 59 , 60 , 61 , 62 ]. PUs are generated from the reaction between amine and isocyanate monomers.…”

“…PUs are generated from the reaction between amine and isocyanate monomers. These MCs are considered valuable owing to their unique features, such as low Tg, rubbery characteristics, as well as their chemical [ 61 ] and mechanical [ 60 ] stability and biocompatibility, [ 63 ] which make them an ideal material for holding liquid in their core even for in vitro applications. In addition to the encapsulation of ionic liquids, which was demonstrated by our group [ 64 ], phase change materials [ 65 ] and more common organic solvents, such as xylene [ 66 ], were found to serve as an efficient platform for implementing PU MCs.…”