1. Small-angle Scattering Study of Mohair Fibres Tjatji Tjebane Instrument Scientist (SANS) tjatji.tjebane@necsa.co.za NECSA-Wits workshop, NVC, 2015/09/11

2. Outline Aim Introduction Mohair fibre SANS Technique Experiments Results and Discussions SANS Applications Summary 2 NECSA-Wits workshop, NVC, 2015/09/11

3. Aim Study mohair fibres using SANS technique Understanding SANS data analysis technique 3 NECSA-Wits workshop, NVC, 2015/09/11

4. Introduction Amorphous Hygroscopicity and changes in fibre structure Textile treatment technology 4 NECSA-Wits workshop, NVC, 2015/09/11

5. Introduction Using heavy water (D 2 O) for contrast enhancement 5

6. Mohair fibre Natural fibre obtained from Angora goat. 6 Exceptional properties: durable, resilient, thermal insulation, flame and crease resistant, e.t.c. Macromolecule - composite fibre - i.e. a fibril-reinforced matrix material with both the fibrils and the matrix consisting of polypeptides, interconnected physically and chemically. Morphology – nanocomposite - (the reinforcing microfibrils have a diameter of about 10 nm) of high complexity with clear hierarchy indicating an enormous degree of self-organisation Protein structure - only the fibrils are regarded as keratins - they being embedded into a protein matrix NECSA-Wits workshop, NVC, 2015/09/11

7. Mohair fibres, cont… 7 Wool contains >170 different proteins Proteins composed of amino acids Amino acids differ in R- side group NECSA-Wits workshop, NVC, 2015/09/11

8. Mohair fibres, cont… 8 NECSA-Wits workshop, NVC, 2015/09/11 Amino acids are joined to form long polymer chains

9. SANS Technique 9 SourceE (meV)λ (Å)T (K) Sub-thermal (cold)0.1 - 10~ 30 - 3~ 1 – 70 NECSA-Wits workshop, NVC, 2015/09/11 |q|= (4π/λ)sin(ϴ)

10. Experiments 10  37.8 µm diameter  CCl 4 cleaned  20% weight D 2 O (Heavy water)  Different S-D positions (0.98 and 5.5 m) NECSA-Wits workshop, NVC, 2015/09/11

11. Results and Discussions 11 NECSA-Wits workshop, NVC, 2015/09/11

12. Results and Discussions, cont… 12 NECSA-Wits workshop, NVC, 2015/09/11 R g = describes the dimensions of a polymer chain

13. NECSA-Wits workshop, NVC, 2015/09/11 Results and Discussions, cont… 13 NECSA-Wits workshop, NVC, 2015/09/11 SampleI bg I 1 (0) /R g1 (nm) I 2 (0) /R g2 (nm) I 3 (0) /R g3 (nm) Dirty8300±9170282±265/ 9.02±0.95 12984±114/ 6.00.±0.63 9946.±99/ 2.61±0.49 Clean6400±80260000±447/ 10.00.±0.10 14000±300/ 6.00.±0.63 9000.±89/ 2.41±0.49

14. NECSA-Wits workshop, NVC, 2015/09/11 Results and Discussions, cont… 14 SampleI bg I 1 (0)/ R g1 (nm) I 2 (0)/ R g2 (nm) I 3 (0)/ R g3 (nm) Dry7600 ± 8739900±199/ 9.70±.98 8900.±94/ 5.98±.76 4050±89/ 5.30±.73 Wet (D 2 O)7600±8791000±301/ 10.10±.10 13000±114/ 7.00±.84 8950±95/ 2.98±.55

15. SANS Applications 15 Soft Condensed Matter  Micelle, micro-emulsion,  Surfactant  polymer systems  multi-phase  block copolymers Bio-molecular Systems  Macromolecular  proteins, viruses,  membranes, vesicles  drug delivery systems  Food science Advanced Materials  Micro-porous systems,  flux lattices, magnetic domains,  metal alloys, precipitation and phase separation

16. Summary SANS (Sub-thermal neutrons) is molecular bond friendly and non-destructive technique Contrast variation method can be used for protein-rich materials SANS is a potential tool for bulk disordered systems Understanding wool fibre props allows different non-damaging treatment 16 NECSA-Wits workshop, NVC, 2015/09/11

17. Acknowledgements Necsa (C. B. Franklyn) CapeWool SA BNC (Gy T ȍ r ȍ k) NRF and IAEA 17 NECSA-Wits workshop, NVC, 2015/09/11

18. THANK YOU 18

19. THANK YOU 19

20. THANK YOU 20

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22. Way forward Increase D 2 O content in the samples Improve analysis Continue development of SANS at Necsa 22 NECSA-Wits workshop, NVC, 2015/09/11

23. Introduction, Mohair (wool) fibre 23

24. SANS @ NECSA, cont… 24 ParameterBNCNecsa q-range (Å -1 )0.003 – 0.500≤ 0. 182