人造黑色素染发材料

Synthetic Melanin Hair Dye

传统仿生人造黑色素聚多巴胺(PDA)染发过程中涉及的过强碱性会使毛发粗糙影响发质,大量的金属离子则存在安全性问题.本工作利用黑色素单体5,6-二羟基吲哚(DHI)能够在温和条件下仅通过空气氧化发生快速聚合的特点,报道了一种通过温和条件在头发表面和内部原位聚合的人造黑色素染发材料.染发色度值L=21,与自然黑发基本一致,洗涤30次后L=25,耐洗涤性良好,染色后头发拉伸强度189 MPa,断裂伸长率51%,相比染色前发质有所改善.研究结果表明,此类染发剂染发条件温和(空气氧化),色度自然,固色持久,有助于改善发质,生物安全性良好,为开发新一代染发剂提供了创新的设计策略和可靠的工具平台.

Hair dyeing has become an indispensable demand and fashion choice in people’s daily lives.The issues of allergy,carcinogenicity,and gene mutation caused by the commonly used chemical hair dye,which mostly comprises p-phenylenediamine and other substances,are becoming noticeable.As a result,there is an urgent need for innovative materials to replace aniline in commercial hair dye.A biomimetic fabrication of polydopamine(PDA)inspired by natural melanin has been reported to have excellent hair dyeing effects.A strong alkaline oxidative environment or metal ion catalysis are usually indispensable for dopamine polymerization.However,excessive alkalinity will make the hair rough and affect its quality,and metal ions may be poisonous.As a result,developing a new type of mild,efficient,safe,and non-toxic synthetic melanin hair dye is an urgent concern.The more reactive melanin monomer 5,6-dihydroxyindole(DHI)may just conduct rapid polymerization by air oxidation,in contrast to DA,which requires demanding oxidation conditions to initiate polymerization.Herein,this work reported a hair dye material that polymerized DHI in situ on the surface and inside of hair under mild conditions.The L value of dyed hair is 30,and L=20 after washing 30 times.The results of the synthetic melanin hair dye to adhere uniformly to the hair surface have been demonstrated by electron microscopy,and some monomers and oligomers will also reach the cortical layer of the hair to polymerize.The poly-DHI(PDHI)structure can engage in a Michael addition reaction with the disulfide bond in the hair to form a covalent coupling due to its high reducibility and highly reactive double bond.The findings of skin sensitization tests demonstrate that using DHI polymerization to dye hair won’t affect human skin or health,even at the greatest concentration permitted.Finally,it can be obtained an efficient,durable,and safe melanin hair dye,which provides an innovative design strategy and a dependable tool platform for the development of a new generation of hair dyes.