The chemistry behind the index.

The single property that defines Polylucia

Silica-based single-mode fiber (SMF-28) has a core refractive index of 1.468. Every existing optical adhesive misses that target by 1–3 % — large enough to cause back-reflection at every fiber-to-chip interface. Polylucia's base polymer (poly-EtVP, internal codename Etaflex) lands at n_D = 1.462 neat, and 1.472 in cross-linked form. That's < 0.4 % deviation — the tightest match commercially available outside expensive fluoropolymer custom resins.

Why aliphatic matters

Polylucia has no aromatic rings, no isocyanates, no BPA derivatives, and no -OH byproducts. That makes it (a) immune to UV-induced yellowing — important for AR/VR and outdoor optics, (b) free from REACH SVHC pressure on PU adhesives, and (c) a structurally clean candidate for the BisGMA dental-resin replacement opening up as the EU SVHC listing and California Prop 65 timer count down.

Cure dynamics

Six vinyl groups per repeat unit. 3.7 s gelation under 365 nm UV-A. 2.4 % cure shrinkage — half that of BisGMA, a third of conventional PUA. For high-precision optical alignment and warpage-sensitive semiconductor packaging, that shrinkage delta is the difference between a passing build and a scrapped wafer.

RF and high-speed data

D_f = 0.0032 at 10 GHz — 5–8× lower than epoxy, 3× lower than thiol-ene systems. That makes Polylucia a serious candidate for CPO underfill and low-D_k EMC in 1.6 T-class transceiver packaging.

Two materials, many formulations

• Etaflex (poly-EtVP) — the photo-cure main resin. UV-curable, optical-grade.
• Detalon (poly-DEtP) — saturated polyester. Flexibilizer and base for liquid-grade index-matching fluids (EF-CLEAVE, EF-IMM, EF-DENT).

Blended ratios give us the full Tg sweep from rigid optical bonding through soft-touch coatings to biodegradable hygiene elastomers — all from the same CO₂-derived feedstock.