Freeform fabrication of three-dimensional structures using a droplet-on-demand process with continuous and frequency modulated material deposition

A method of fabricating a matrix comprising a three-dimensional structure, comprising:

• forming a negative three-dimensional template using droplet-based freeform printing, wherein forming the negative three-dimensional template comprises:
• depositing a structural material through one or more nozzles onto a surface of a substrate by droplet-based freeform printing to form the negative three-dimensional template as one or more three-dimensional structures comprising one or more cross-sectional dimensions, the structural material comprising:
• water, an aqueous solution, camphene, or combinations thereof;
• and
• controlling a droplet ejection frequency while depositing the structural material to form a three-dimensional structure of the one or more three-dimensional structures such that the three-dimensional structure is formed from droplets ejected at different frequencies,
• wherein the structural material undergoes a liquid-to-solid transition after deposition of the structural material,
• wherein the one or more cross-sectional dimensions are controlled by the droplet ejection frequency, and
• wherein the droplet ejection frequency is controlled such that the liquid-to-solid transition of a droplet of the structural material does not undergo a complete liquid-to-solid transition before a subsequent droplet of the structural material is deposited;
• depositing a matrix material over the negative three-dimensional template and at least a portion of the surface of the substrate;
• and
• solidifying the matrix material to form a matrix comprising the one or more three-dimensional structures of the negative template.

A method of forming a three-dimensional structure using droplet-based freeform printing comprising:

• depositing a structural material through one or more nozzles onto a surface of a substrate by droplet-based freeform printing to form one or more three-dimensional structures comprising a three-dimensional structure having different cross-sectional dimensions, the structural material comprising (i) water, an aqueous solution, camphene, or any combination thereof, and (ii) carbon nanotubes, graphene oxide, MXenes, metal nanoparticles, or any combination thereof,
• wherein the structural material undergoes a liquid-to-solid transition after deposition of the structural material,
• wherein the different cross-sectional dimensions are controlled by modulating a droplet ejection frequency while forming the three-dimensional structure,
• wherein the droplet ejection frequency is controlled while depositing the structural material such that a liquid-to-solid transition of a droplet of the structural material does not undergo a complete liquid-to-solid transition before a subsequent droplet of the structural material is deposited.