Silica fillers were coated by plasma polymer coatings of 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allyl mercaptan and allyl alcohol using RF plasma (13.56 MHz). The coated fillers were then mixed with biphenyl epoxy, phenol novolac (curing agent) and/or triphenylphosphine (catalyst), and subjected to DSC analyses in order to elucidate the chemical reaction between functional moieties in the plasma polymer coatings and the epoxy resin. For comparison, samples were also prepared with liquid monomers, biphenyl epoxy, phenol novolac and/or triphenylphosphine. In addition, silicon wafers were coated by plasma polymerization and analyzed by FT-IR. Only the samples with 1,3-diaminopropane and allylamine plasma-polymer-coated silica fillers showed heat of reaction peaks when they were mixed with biphenyl epoxy resin, while these samples as well as the sample with pyrrole plasma-polymer-coated silica fillers exhibited beat of reaction peaks when mixed with both biphenyl epoxy and phenol novolac (curing agent). However, all plasma polymer samples exhibited heat of reaction peaks when they were mixed with biphenyl epoxy, phenol novolac and triphenylphosphine. The samples with liquid monomers showed a similar behavior, but the peaks appeared in the lower temperature range.