Refractive Index Distribution of Graded Index Poly(methyl methacrylate) Preform Made by Interfacial-Gel Polymerization

Abstract

A graded index poly(methyl methacrylate) (PMMA) preform has been made by a novel interfacial-gel polymerization procedure, in which polymerization was performed in a PMMA tube and a dopant, bromobenzene (BB), was used as a higher refractive index molecule. A detailed mechanism of the graded index formation is given and simulated according to the free volume theory and its application in a high-conversion polymerization system. Under the assumption that polymer concentration distributes in the form of ω ) a exp(r) + b at the radial direction of the tube, a quadratic distribution of refractive index on the cross section of the preform is obtained. The result is identical with experiments performed by the interfacial-gel polymerization.

Synthesis and Characterization of Functionally Gradient Materials Obtained by Frontal Polymerization

“…13 Some of the most interesting applications of FGMs include the design of aerospace materials with very high thermal gradients, 14 artificial tissues for the replacement of bones 15 or teeth, 16 materials for defense with low crack propagation, 17 materials for energy conversion devices and thermal barriers, 18 and gradient refractive index materials for optoelectronics. 19 Gradient polymers that have been processed so far include gradient fiber composites, 20 gradient interpenetrating polymer networks, 21 polymers with a gradual composition of plasticizer, 22 gradient refractive index materials, 23 polyacrylates with nonlinear dye gradients, for which Pojman and Chekanov exploited a frontal polymerization (FP) approach. 24 It is noteworthy that with respect to the majority of the FGM production methods, FP has more potential.…”

Isothermal Frontal Polymerization

“…There have been several coordinated studies of experimental and mathematical IFP including those of no-dopant IFP, IFP with inhibitor, IFP systems that produced TFP under certain conditions, and IFP with dopant [11,6,38,40,42]. One of the most recent comparisons was a collaborative study of no-dopant IFP to compare propagation distances and gradient profiles for the parameter changes of initiator concentration and of cure temperature [6].…”

New insight into isothermal frontal polymerization models: Wiener's method to determine the diffusion coefficients for high molecular-weight poly(methyl methacrylate) with neat methyl methacrylate

“…To produce IFP GRINs, which have been used as waveguides, laser applications, and other optical applications, a dopant (a second monomer or other material, e.g. a dye) can be added to the monomer solution [12,[14][15][16][17][18][19][20]. Spade et al discuss the mechanism to include the dopant, and all material in the subsequent sentences are from Ref.…”

“…One hindrance to these models is the lack of information in the literature on diffusion coefficients for the components used in IFP. (Much of the published experimental work on IFP used the monomer methyl methacrylate (MMA) with a high molecular-weight poly(methyl methacrylate) (PMMA) seed or used MMA derivatives [12,[15][16][17][18]20,23,[28][29][30].) Because diffusion coefficients for the exact system were not available, the mathematical models used published diffusion coefficients for low molecular-weight PMMA systems solvated by other solvents (e.g.…”