Monodispersed particles fabricated by microfluidic device
According to various embodiments the present disclosure provides porous particles and methods and apparatus for forming porous microparticles. According to a specific embodiment, the present disclosure provides microparticles with multi-nodal porosity and methods for forming the same. According to a still further embodiment, the present disclosure provides microfluidic device-based methods for forming microparticles with multi-nodal nanoporosity. Furthermore, the present disclosure provides populations of monodisperse mesoporous microparticles with multi-nodal nanoporosity and methods and apparatus for forming the same. According to a specific embodiment, the present disclosure provides populations of monodisperse mesoporous microparticles formed using a microfluidic device.
1. A method for forming a monodisperse spherical mesoporous microparticles comprising:
providing a microfluidic device comprising:
a main channel;
a first channel fluidly connected to the main channel, and
a second channel fluidly connected to the main channel downstream of the first channel;
delivering a mixture of a polymer precursor and a cationic surfactant though the main channel of the microfluidic device;
delivering oil via the first channel to form emulsion droplets;
delivering an oil and nonionic surfactant mixture via the second channel to form a microemulsion phase that penetrates the emulsion droplets;
removing the solvents and allowing polymerization of the polymer precursor so as to produce a monodisperse population of spherical microparticles having pores formed from templating the microemulsion droplets.
2. The method of claim 1 wherein the polymer precursor is a silica precursor.
3. The method of claim 1 wherein the nonionic surfactant is soluble only in the oil phase.
4. The method of claim 3 wherein the cationic surfactant is dissolved only in the aqueous phase.
5. The method of claim 1 wherein the nonionic surfactant is Abil EM90.
6. The method of claim 1 wherein the cationic surfactant is CTAB.
7. The method of claim 1 wherein the larger diameter pores are between 10 and 40 nm in diameter and the smaller diameter pores are between 3 and 7 nm in diameter.
8. A method of forming a monodisperse population of mesoporous microparticles, the method comprising:
delivering a solution containing a mixture of a polymer precursor and a cationic surfactant to the main channel of a microfluidic device;
delivering oil to the main channel under suitable conditions that the polymer precursor solution forms emulsion droplets in the microfluidic device;
allowing the emulsion droplets to flow through the microfluidic device;
delivering oil and a nonionic surfactant-to the formed emulsion droplets in the microfluidic device under suitable conditions that the nonionic surfactant is able to permeate the emulsion droplets and form microemulsion oil droplets within the emulsion droplets;
collecting the microemulsion containing emulsion droplets; and
removing the solvents, thereby allowing the polymer precursor to polymerize and template the microemulsion oil droplets, thereby forming a monodisperse population of porous microparticles.
9. The method of claim 8 wherein the cationic surfactant is soluble only in the aqueous phase and the nonionic surfactant is soluble only in the oil phase.
10. The method of claim 8 wherein the cationic and nonionic surfactants significantly decrease the interfacial tension when adsorbed.
11. The method of claim 1 wherein removal of the solvents is performed by evaporation at ambient temperature and pressure.
12. The method of claim 1 wherein the emulsion droplets are formed at or near the intersection of the main channel and the first channel.
13. The method of claim 1 wherein the microemulsion phase penetrates the droplets at or near the intersection of the main channel and the second channel.