2010 TRI/PRINCETON CONFERENCE 261 Polyquaternium-7, Polyquaternium-10, Polyquaternium-44, Polyquaternium-87, and Guar Hydroxypropyl Trimonium Chloride combined with silicone emulsion. The physical UST measurements wer complemented by sensoric evaluations of hair dressers: Their results correlated well with the UST results. The same trend also showed in the measurements of the combing force reductions. The graph in Figure 3 shows the force reduction FR in % of different samples as well as the combing force data in %. It is visible that silicone containing conditioning systems have higher values meaning less friction and less resistance to combing it is remarkable that one conditioning polymer, the Polyquaternium-87 (1), reveals the same effect with- out any silicone. The typical “silicone feel” on hair in terms of smoothness, which is currently the favored attribute, can also be observed taking a closer look to the wet combing curve profi les as well as the dry friction. The correlation between sensoric ranking and co-depositioning of silicone and polymer is shown in Figure 4. A new method for the investigation of single fi ber-fi ber interactions was set-up on the AFM (2). In order to prepare a modifi ed cantilever as a hair probe, standard single bleached Caucasian hair tresses were used. Hair fragments were cut with a P.A.L.M. Microbeam Figure 2. Options for conditioning polymers. Figure 3. Correlation of wet comb force data and wet UST data.

JOURNAL OF COSMETIC SCIENCE 262 Figure 4. The correlation between sensoric ranking and co-depositioning of silicone and polymer is shown +++ means well conditioned, “silicone feel.” Figure 5. One hundred vertical force distance curves of a single hair-hair experiment by AFM to show the reproducibility of one spot of a hair in dry state. laser (3). Then, these fragments of 50 μm diameter were glued to tipless cantilevers. We used a two component adhesive on an epoxy resin. Additionally, we prepared a hair as substrates and fi xed them with an industrial double tape on microscope slides. The mea- surements were done with this set-up on a MFP-3D AFM (4). For measurements in water, we used a closed fl uid cell. Conventionally, colloidal particles used in colloidal probe AFM have a diameter dimen- sion of up to 50 microns. Consequently, the hair is cut into units whose length is smaller than the hair diameter for avoiding diffi culties due to inertia, hydrodynamic friction or weight of the attached object. Figure 5 shows a representative force distance curve of a vertical single hair-hair measure- ment experiment in air with a relative humidity of 30 ± 5%. There are 100 curves plotted to emphasize the reproducibility at a single spot. The standard deviation of one position was around 2.3% ± 0.4%.