Beam Interactions with Materials 8 Atoms ELSEVIER Nuclear Instruments and Methods in Physics Research B 132 (1997) 697-703 Non-ionic surfactant concentration profiles in undamaged and damaged hair fibres determined by scanning ion beam nuclear reaction analysis P.M. Jenneson a,*, A.S. Clough a, J.L. Keddie a, J.R. Lu b, P. Meredith ’ a zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Department of Physics, University of’ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJ Sure?. Guildford, Surrey. GlJ2 5XH, UK b Department zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA of Chemistry, University of Surrey. Guildford. Surrey, GE 5XH, UK ’ Procter & Gamble (Health and Beauty Care) Limited. Rusham Park. Egham, Surrey, TW 20 9NW , UK Received 18 July 1997 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONML Abstract Nuclear Reaction Analysis (NRA) was used with a scanning MeV 3He ion microbeam to determine the extent of permeation and segregation of a deuterated non-ionic surfactant (dCr?ES) into virgin (undamaged) and alkalinic perm damaged hair fibres. 2-D concentration maps show an accumulation of deuterated surfactant in the cortex and medulla of both the virgin and damaged hair. By normalising to the matrix carbon, surfactant levels in the damaged hair were found to be three times higher than in the undamaged hair. This is the first reported direct spatial evidence of the pen- etration of surfactant into the centre of hair fibres. Furthermore it is the first application of NRA to this type of com- plex biological matrix. 0 1997 Elsevier Science B.V. 1. Introduction The transport, segregation and deposition of surface active agents, or surfactants, into hair has important implications for the cosmetics in- dustry. Surfactants are a primary component of cosmetics such as shampoo [l]. In human hair fibres, an outer layer of cuticle (thickness of N 3-5 urn) surrounds an inner core (diameter - 50-90 urn) consisting of the cortex ‘Corresponding author. Tel.: 44 1483 300800-2694; fax: +44-1483-259501: e-mail: p.jenneson@surrey.ac.uk. and the medulla, as shown in Fig. 1. The cuticle of damaged hair fibres has previously been as- sumed to be more porous than in undamaged hair fibres [l] and therefore likely to allow the surfact- ant and water solution to penetrate into the cortex and medulla. Surfactant (ionic or non-ionic) uptake into hair has previously not been measured with high spatial resolution. Robbins et al. [2] however have studied the zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK total amount of surfactants absorbed on and into hair fibres using radiotracer analysis. They state that the diffusion of surfactants into hair is very slow and it takes days for an average-size surfactant to completely penetrate cosmetically 0 168-583X/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PUSO168-583X(97)00500-4