734 JOURNAL OF COSMETIC SCIENCE RINSE-OFF CONDITIONER FORMULATION The rinse-off conditioner formulation used for the studies is found in Table I. Deionized water was added to the mixing vessel and heated to 70°C. With moderate agitation, the hydroxyethyl cellulose was dispersed until fully dissolved. The temperature was decreased to 60°C, and cetearyl alcohol and PEG-100 stearate, glyceryl stearate, and oil or oil gel were added. The conditioner was mixed for 3 min, and then tetrasodium EDTA was added and mixed for 3 min. When the temperature was below 40°C, the phenoxyethanol and methylisothiazolinone was added. Additional water was added, and the final pH of all conditioners was approximately 5. SECONDARY ION MASS SPECTROMETRY IMAGING Organic depth profiling of deposited layers can be accomplished using secondary ion mass spectrometry (SIMS). This method utilizes an Ar cluster ion beam (gas cluster ion beam) to gently etch the surface followed by analysis with a Bi 3 + ion beam with sensitivity to the molecular and elemental composition of the top 2 nm. In this case delayed extraction was used to obtain high-resolution images during depth profiling. Data were collected using an IONTOF V SIMS (IONTOF, Münster, Germany) instrument with a primary analysis beam operating at 30 kV using bunched Bi 3 + ions in a 200 μm random raster with 256 × 256 pixels. Depth profiling was accomplished using a 2.5 kV Ar 1000 + ion beam in noninterlaced mode with 1 scan/1 sputter cycle across 500 μm square raster areas. Data were analyzed using Surface Lab 7.2.125200 (IONTOF, Münster, Germany). RESULTS The main component of coconut oil is the ester of lauric acid, a saturated, linear dodecyl (C12) hydrophobe. To target the greatest compatibility with coconut oil, which contains mostly short-chain fatty esters, we selected a polymer composition with 80% IBMA and 20% EHMA, stabilized with a small level of MAA and lightly cross-linked for maximum viscosity enhancement. The compatibility of these acrylic copolymers is highlighted in Table I Rinse-Off Conditioner Formulation Used for the Studies Control Coconut oil only 6% acrylic copolymer in coconut oil gel Ingredient (INCI name) wt% wt% wt% Water 95.8 93.8 93.8 Hydroxyethyl cellulose 1.5 1.5 1.5 Tetrasodium EDTA 0.2 0.2 0.2 Cetearyl alcohol 1.0 1.0 1.0 PEG-100 stearate and glyceryl stearate 1.0 1.0 1.0 Oil or oil gel 0.0 2.0 2.0 Phenoxyethanol and methylisothiazolinone 0.5 0.5 0.5 EDTA: ethylenediaminetetraacetic acid INCI: International Nomenclature Cosmetic Ingredients.

735 ENHANCED NATURAL OIL DEPOSITION Figure 2, and the rheological profile is presented in Figure 3. The clarity of the structured coconut oil is comparable to the native coconut oil, but the viscosity, particularly at low- shear rates, was increased by two to four orders of magnitude when 4% or 6% acrylic copolymer was used, respectively. To demonstrate the effectiveness of structured coconut oil for improved deposition, we first compared an unstructured oil with a structured oil for deposition and retention on bleached hair tresses. Shown below in Figure 4, hair tresses were treated with coconut oil or structured coconut oil (containing 2% acrylic copolymer), left to dry overnight, and then washed with shampoo the following day. Six tresses were used for each condition, and the level of oil retained on the hair fibers was observed to be 2.5 times that of the unstructured coconut oil. Interestingly, despite slight changes in polymer composition, a similar 2 to 3 times increase was observed for all polymers in this class of oil structurants. Figure 3. Overlay of flow curves of (refined) coconut oil containing acrylic copolymer samples at different concentrations. Figure 2. Images of refined coconut oil (first panel), 2% acrylic copolymer in coconut oil (second panel), 4% acrylic polymer in coconut oil (third panel), and 6% acrylic polymer in coconut oil (fourth panel).