TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The fluid (H1) complies with a structure of formula (RH1-O-(RHf)r-RH) (IA) or (RH1-O-J-(O)j-RH) (IB), preferably hydrofluoroether (fluid (HFE)), i.e. a compound comprising, in addition to carbon, fluorine, and ether oxygen atoms, one or more hydrogen atoms. The fluid (HFE) complies with a structure of formula (RH12-O-(RHf)r-RH11) (IIA) (preferred) or (RH12-O-J-(O)j-RH11) (IIB). The additive (N) is carbon nanotubes. The functional PFPE (F1) is a compound complying with structure of formula (T1-(CFX1)p1-O-Rf-(CFX1)p2-T2), where the functional PFPE (F1) has a structure of formula ((X2-(CF2CF(CF3)-O)n11CF2COO-)M), ((X2-(CF2CF(CF3)-O)n11CF2COO-)2M1), ((HO)2OP-O(CH2CH2O)p3-CH2CF2O-(CF2CF2O)m1(CF2O)n1-CF2CH2O(CH2CH2O)p3-PO(OH)2), (HO-CH2CF2O(CF2O)n2(CF2CF2O)m2CF2CH2-OH), (HO(CH2CH2O)n33CH2CF2O(CF2O)n3(CF2CF2O)m3CF2CH2(OCH2CH2)n33OH) or (MOOC-CF2O-(CF2O)n4(CF2CF2O)m4CF2COOM).RH, RH1 = -CmF2m+1, -CnF2n+1-hHh, -CpF2p+1-h1Xh1, -CzF2z-O-CyF2y+1 or -CuF2u-u1Hu1-O-CwF2w+1-w1Hw1;RH11, RH12 = -CmF2m+1, -CnF2n+1-h-Hh, -CzF2z-O-CyF2y+1 or -CuF2u-u1Hu1-O-CwF2w+1-w1Hw1;X = halo comprising Cl (preferred), Br or I;RHf = fluoropolyoxyalkene chain comprising repeating units of RHo (preferably -(CF2O)a-(CF2CF2O)b-, -(CF2-(CF2)z1-CF2-O)b1- or -(C3F6-O)c-(C2F4-O)b-(CFLo-O)t-);RHo = -CFX1O-, -CF2CFX1O-, -CFX1CF2O-, -CF2-CF2-CF2-O- or -CF2-CF2-CF2-CF2-O-;Lo, X1 = -F or -CF3;J = 1-12C divalent hydrocarbon radical, aliphatic or aromatic (preferably an 1-6C aliphatic divalent hydrocarbon group, e.g. -CH2-, -CH2CH2- or -CH(CH3)-);Rf = fluoropolyoxyalkene chain comprising repeating units of Ro;Ro = -CFX1O-, -CF2CFX1O-, -CF2-CF2-CF2-O-, -CF2-CF2-CF2-CF2-O- and/or -(CF2)k-CFZ-O-;Z = group of formula (-ORf1T3);Rf1 = fluoropolyoxyalkene chain comprising a number of repeating units 0-10 (where the recurring units are -CFX1O-, -CF2CFX1O-, -CF2CF2CF2O- or -CF2CF2CF2CF2-O-);T3 = 1-3C perfluoroalkyl;at least one T1, T2 = heteroatom comprising O, S, N and/or P;the remaining T1,T2 = H, halo or 1-30C end-group;X2 = halo (preferably Cl or F);M = univalent cation comprising H+, Na+, K+ or NH4+;M1 = divalent cation comprising Ca++, Mg++ or Zn++;n, m, p, z, y, u, w = 1-8 (preferably 1-7); eitherh, h1, u1, w1 = greater than or equal to 1; andh = less than or equal to 2n+1; andh1 = less than or equal to 2p+1; andu1 = less than or equal to 2u; orw1 = less than or equal to 2w+1;r = 0-1 (preferably 1);j = 0-1; eithera, b = integers up to 100; anda = greater than or equal to 0; andb = greater than or equal to 0; anda+b = greater than 0 (preferably each of a and b is greater than 0); orb/a = 0.1-10;z1 = 1-2;b1 = integer up to 100; eitherb, t, c = integer up to 100; orc = greater than 0; orb = greater than or equal to 0; andt = greater than or equal to 0 (preferably b and t greater than 0); andc/b = 0.2-5; or(c+b)/t = 5-50;p1, p2, k = 0-3;n11 = 2-100 (preferably 2-60);m1, n1, m2, n2, m3, n3, m4, n4 = integers;m1/n1, m2/n2, m3/n3, m4/n4 = 0.1-10 (preferably 0.2-5);m1+n1, m2+n2, m3+n3, m4+n4 = 2-100 (preferably 2-60);p3 = 0-3 (preferably 1-3); andn33 = 1-3.Provided that: at least one of RH12 and RH11 in formula (IIA) is a -CnF2n+1-h-Hh group or a -CuF2u-u1Hu1-O-CwF2w+1-w1Hw1 group. EXAMPLE - Typical heat transfer composition comprised (in g): multiwall carbon nanotubes (0.1); functional (per)fluoropolyether (1); and H-Galden ZT 130 (RTM: Hydrofluoroether) (98.9).