3d printing of composition-controlled copolymers

Abstract

A computer-controlled system for forming composition-controlled objects using 3D printing includes two or more liquid reactant reservoirs, and a mixing sub-system for mixing the two or more liquid reactant compositions, which in turn includes a flow control sub-system to control a mass ratio of the mixed two or more liquid reactant compositions. The computer-controlled system further includes a scanning sub-system that, under control of the computer, causes relative motion of a mixed liquid reactants nozzle over a substrate; thereby depositing the mixed liquid reactant compositions onto the substrate. The system still further includes an illuminations system, operated under control of the computer, to polymerize the deposited mixed liquid reactant compositions.

We claim: 
     
         1 . A computer-controlled system for forming a composition-controlled object using 3D printing, comprising:
 two or more reservoirs, each reservoir capable of storing a liquid reactant composition, each liquid reactant composition differing in chemical properties;   a mixing sub-system for controlling liquid reach composition flow from the reservoirs, homogeneously mixing the liquid reactant compositions, and discharging homogeneously-mixed liquid reactant compositions;   a stage configured to support a substrate that receives the discharged homogeneously-mixed liquid reactant compositions;   an illumination sub system that polymerizes the received homogeneously-mixed liquid reactant composition; and   a computer control sub-system comprising:
 a non-transitory computer-readable storage medium having stored thereon, machine instructions that when executed, cause production of a 3D composition-controlled object, and 
 a processor that executes the machine instructions to:
 control a mass ratio of each liquid reactant composition in a homogeneous mixture of the liquid reactant compositions; 
 cause relative motion between a homogeneously-mixed liquid reactants nozzle and the substrate; 
 deposit the homogeneously-mixed liquid reactant compositions onto the substrate; and 
 operate the illumination sub-system to polymerize the deposited homogeneously-mixed liquid reactant compositions, comprising, throughout an entire deposition process for forming the 3D composition-controlled object, as the deposited homogeneously-mixed liquid reactant compositions touch the substrate, operating the illumination sub-system to rapidly polymerize the compositions. 
 
   
     
     
         2 . The system of  claim 1 , wherein the liquid reactant compositions in the reservoirs comprise reactant(s), initiators, porogenic particles, reinforcing particles, solvent(s), and combinations thereof. 
     
     
         3 . The system of  claim 2 , wherein the reactants are chosen from a group consisting of monomers and monomer mixtures that form composition-controlled copolymers at different degrees of monomer to polymer conversion. 
     
     
         4 . The system of  claim 2 , wherein the initiators are chosen from a group consisting of initiators for free-radical polymerization, cationic polymerization, and anionic polymerization. 
     
     
         5 . The system of  claim 2 , wherein the porogenic particles are chosen from a group consisting of water-soluble sugar, water-soluble salt, and organic solvent soluble polymer particles. 
     
     
         6 . The system of  claim 2 , wherein the reinforcing particles are chosen from a group consisting of metal oxide particles and nanoparticles. 
     
     
         7 . The system of  claim 1 , wherein the mass ratio of the liquid reactant compositions is controlled by flow rate and mixture in a container within the nozzle. 
     
     
         8 . The system of  claim 1 , wherein the mass ratio of the liquid reactant compositions is controlled by flow rate and mixture in a container immediately adjacent to the nozzle. 
     
     
         9 . The system of  claim 1 , wherein the degree of monomer to polymer conversion is controlled using illumination intensity and irradiation time. 
     
     
         10 . The system of  claim 1 , further comprising a post-printing treatment sub system for submitting printed products to post printing treatments including one or more of soaking in water or aqueous solutions, soaking in organic solvents, and annealing. 
     
     
         11 . The system of  claim 1 , wherein the 3D composition-controlled objects comprise dental devices for dental restorative material, denture, orthodontic treatment, dental implant, dental tissue regeneration, and dental tissue engineering. 
     
     
         12 . The system of  claim 1 , wherein 3D composition-controlled objects comprise optical devices with spatially controlled optical properties, including refractive index, transmission, reflectance, color, polarization, and glossiness. 
     
     
         13 . The system of  claim 1 , wherein the nozzle is fixed and the processor executes machine instructions to move the stage to generate the relative motion. 
     
     
         14 . A system for composition-controlled printing of a three-dimensional (3D) object, comprising:
 a plurality of reservoirs, each reservoir containing a liquid reactant composition different from liquid reactant compositions in others of the plurality of reservoirs;   a liquid reactant composition flow control sub-system comprising:
 a reservoir discharge valve for each of the plurality of reservoirs, 
 a mixing chamber having an intake connected to a discharge of the reservoir discharge valves and a mixing chamber discharge, and 
 a mixing valve and a scanning nozzle connected to the mixing chamber discharge; 
   an illumination sub-system;   a scanning stage;   a non-transitory, computer-readable storage medium having stored therein machine instructions for composition-controlled printing of 3D objects; and   a computer, wherein the computer executes the machine instructions to control flows of the different liquid reactant compositions from the reservoirs into the mixing chamber, wherein the computer executes the machine instructions to:
 control a composition percentage of each of the different liquid reactant compositions in the mixing chamber comprising the computer executing the machine instructions to individually adjust the discharge valve from each of respective ones of the reservoirs, 
 mix homogeneously, the different liquid reactant compositions in the mixing chamber thereby producing a homogeneously-mixed liquid reactant composition, and 
 control mechanical properties of the 3D printed object by a plurality of step-wise depositions and polymerizations of the homogeneously-mixed liquid reactant composition, wherein the computer executes the machine instructions to:
 deposit variable amounts of the homogeneously-mixed liquid reactant composition onto a substrate by controlling the mixing valve and scanning nozzle; and 
 polymerize the deposited variable amounts of the homogeneously-mixed liquid reactant composition by controlling a light source such that, throughout deposition, as the deposited homogeneously-mixed liquid reactant composition touches the substrate, the computer executes machine instructions to operate the light source to rapidly polymerize the deposited homogeneously-mixed liquid reactant composition. 
 
   
     
     
         15 . The system of  claim 14 , wherein the computer controls a composition percentage by controlling one or more of a weight percentage, a volume percentage, and a molar ratio percentage of each of the different liquid reactants in the mixing chamber. 
     
     
         16 . The system of  claim 14 , wherein the liquid reactant compositions form azeotropic compositions, and wherein the computer controls the mechanical properties of the 3D printed object by controlling individual flows from the respective reservoirs to achieve a desired molar ratio of the different liquid reactants in the mixing chamber. 
     
     
         17 . The system of  claim 14 , wherein the computer controls the mechanical properties of the 3D printed object by controlling the variable amounts during one or more of the step-wise depositions and polymerizations. 
     
     
         18 . The system of  claim 14 , wherein the computer controls the mechanical properties of the 3D printed object by controlling the intensity and duration of an illumination source of the illumination sub-system during one or more of the step-wise depositions and polymerizations. 
     
     
         19 . The system of  claim 14 , wherein the mixing chamber and mixing valve are combined. 
     
     
         20 . A non-transitory, computer-readable storage medium having encoded thereon, machine instructions for composition-controlled three-dimensional (3D) printing, that, then executed by a processor, cause the processor to:
 using two or more liquid reactant compositions disposed in respective two or more reservoirs, mix the two or more liquid reactant compositions by controlling a mass ratio of the mixed two or more liquid reactant compositions;   scan a mixed liquid reactants nozzle over a substrate;   deposit the mixed liquid reactant compositions onto the substrate; and   operate a light source to polymerize the deposited mixed liquid reactant compositions, by, throughout the entire method for forming a 3D composition-controlled product, as the deposited mixed liquid reactant compositions touch the substrate, operating the light source to rapidly polymerize the compositions.