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AFM Images of the hair cuticle surface with and without thermal treatment. (a) Not thermally treated. (b, c, d) Thermally treated at 232°C.
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Hot flat irons are used to create straight hair styles. As these devices operate at temperatures over 200 °C they can cause significant damage to hair keratin. In this study, hair thermal damage and the effect of various polymeric pretreatments were investigated using FTIR imaging spectroscopy, DSC, dynamic vapor sorption (DVS), AFM, SEM, and therm...
Context in source publication
Context 1
... PROTECTION OF THE HAIR SURFACE BY COSMETIC PRETREATMENT Figure 7 shows atomic force microscopy (AFM) images of the surface of the hair cuticle with and without thermal treatment. The AFM images indicate that thermal treatment at 232°C causes damage on the cuticle surface, including cracks, holes from over-heating, and formation of micropores. ...
Citations
... Hereupon, many compounds, such as the silicones, have been widely used as heat protectants due to their high resistance to heat, water or oxidizing agents. In addition, lipids and silicones are good electrical insulators and film formers, preventing the loss of water and keeping the hair hydrated, while improving the sensory aspect, in terms of combing and disentangling (DAVIS et al., 2011;RELE;MOHILE, 2003;ZHOU et al., 2011). ...
... Among the lipid components routinely used in hair heat protectants, there are cetostearyl alcohol, shea butter and coconut oil. These products are commercially available in the form of creams and leave-on sprays (rinse off) to be utilized before or post-thermal exposure as pre-treatments or hair restoratives (DAVIS et al., 2011;RELE;MOHILE, 2003;ZHOU et al., 2011). ...
Thermal procedures aiming hair dressing, such as hair brushes, hair dryers or hair straighteners, usually involve higher temperatures, which progressively damages the hair fiber structure. The search for heat protectants for reducing this thermal damage has been growing, especially containing green components from vegetable source. To be efficient, the heat protectants should adequately spread throughout the entire hair shaft, covering the entire surface to be protected. Thus, the influence of the lipids in the in vitro spreadability of heat protectants was determined in this study. This influence was determined in a central composite rotational design 23, and spreadability was the dependent variable. Cetostearyl alcohol, shea butter and coconut oil concentration ranged between 0.64 and 7.36% (w/w) and the emulsions were prepared by hot homogenization with mechanical stirring. In vitro spreadability was determined by using an apparatus containing a square glass plate positioned on a circular plate with a 1 cm diameter hole in the center, on which a fixed amount of sample was applied to be pressed onto the surface by a fixed weight (5 g). Changes in the concentration of the components directly influenced the product spreadability (p < 0.05), which was higher around the central point for shea butter and coconut oil concentrations (4%) and at low concentrations of cetostearyl alcohol (0.64%). The studied components directly influenced the spreadability of the final product, which can be optimized in a rational pathway to obtain an adequate coverage throughout the hair shaft and desired thermal protection. Keywords: Cosmetics. Factorial design. Hair coverage. Hair damage. Thermoprotective. ResumoProcedimentos térmicos para pentear os cabelos, como escovas, secadores ou chapinhas, geralmente envolvem temperaturas elevadas, o que danifica progressivamente a estrutura da fibra capilar. A busca por protetores térmicos para redução deste dano térmico vem crescendo, principalmente contendo componentes verdes de origem vegetal. Para serem eficientes, os protetores térmicos devem se espalhar adequadamente por toda a haste capilar, cobrindo toda a superfície a ser protegida. Assim, a influência dos lipídios na espalhabilidade in vitro de protetores térmicos foi determinada neste estudo. Essa influência foi determinada em um delineamento composto central rotacional 23 e a espalhabilidade foi a variável dependente. As concentrações de álcool cetoestearílico, manteiga de karité e óleo de coco variaram entre 0,64 e 7,36% (p/p) e as emulsões foram preparadas por homogeneização a quente com agitação mecânica. A espalhabilidade in vitro foi determinada por meio de um aparato contendo uma placa de vidro quadrada posicionada sobre uma placa circular com um orifício central de 1 cm de diâmetro, na qual foi aplicada uma quantidade fixa de amostra para ser pressionada na superfície por um peso fixo (5 g). A variação na concentração dos componentes influenciou diretamente na espalhabilidade do produto (p < 0,05), sendo maior em torno do ponto central para as concentrações de manteiga de karité e óleo de coco (4%) e em baixas concentrações de álcool cetoestearílico (0,64%). Os componentes estudados influenciaram diretamente na espalhabilidade do produto final, que pode ser otimizado de forma racional para se obter uma cobertura adequada em toda a haste capilar e a proteção térmica desejada. Palavras-chave: Cosméticos. Planejamento Fatorial. Cobertura CAPILAR. Danos Capilares. Termoprotetor
... Chemical treatments during perming and dyeing cause damage to keratin and cuticles. In addition, excessive or inappropriate use of heating devices such as hair irons and dryers causes severe hair damage such as protein denaturation and epidermal peeling [5,6]. ...
... Hot flat irons operate at temperatures over 200 °C, and they can cause significant damage to hair keratin. Zhou et al. (2011) reported that, thermally stressed hair causes an increase in hair breakage when subjected to combing. Polymeric pretreatments of hair provide thermal protection against thermal degradation of keratin in the cortex and hair surface. ...
... In addition, the alkyl modification also allows for less surfactant to be used in mousse products since it tends to foam in these types of systems. Lastly, when applied from a leave-on product, VP/DMAPMA/MAPLDMAC copolymer was shown to provide color protection to hair that was treated with oxidative hair color after being exposed to multiple shampoo cycles as well as protection from hair damage caused by thermal styling appliances [46,47]. This polymer is a good example of how the appropriate monomers combined with VP can have a dramatic effect on the performance benefits in multiple hair care applications. ...
... Hair damage from hot flat irons and the protection that polymer pretreatments afford to hair was studied by various testing techniques [47]. Several polymers containing the VP monomer were shown to reduce hair damage, namely, VP/DMAPMA copolymer, VP/ DMAPMA/MAPLDMAC copolymer, VP/AA/LMA copolymer, and a polyelectrolyte complex of PVM/MA copolymer and VP/MAPTAC copolymer. ...
The key ingredients making up the framework of the formula must perform in the constraints of the intended chemical environment, such as in the high surfactant load of a shampoo or the extremes of pH found in household cleaners. In order to fully explain the features and benefits of polymer treatments on human hair to achieve cosmetic effects, such as care, styling, and treatment, it is essential to first consider the nature of hair and the important facets of its behaviour. Polymer adhesion to the surface of hair is a prerequisite for its use as a hair styling polymer. The chapter describes the technologies in the home care market space that include poly(vinylpyrrolidone) (PVP), poly(vinyl caprolactam), and their derivatives. PVP and its derivatives have been formulated into laundry care products, such as liquid detergents, to counteract dye transfer. Molecular modeling was also used to show the importance of conformational interactions of dyes with PVP.
... Hair is basically made up of proteins that, when subjected to high temperatures (~200 • C), undergo a change in conformation, and degradation in a measurable amount, in addition to the formation of micropores resulting from the disintegration of the cells of the cuticle that result in wire breakage. Zhou et al. (2011) carried out a study to evaluate the performance of some polymers in capillary thermal protection. They concluded that pre-treatment of hair with selected high molecular weight polymers containing film-modifying groups or hydrophobic units, such as VP/acrylates/lauryl methacrylate copolymer, polyethylene carbonate (PEC), and polyquaternium-55, clearly provide thermal protection to the hair, evicting damage [60]. ...
... Zhou et al. (2011) carried out a study to evaluate the performance of some polymers in capillary thermal protection. They concluded that pre-treatment of hair with selected high molecular weight polymers containing film-modifying groups or hydrophobic units, such as VP/acrylates/lauryl methacrylate copolymer, polyethylene carbonate (PEC), and polyquaternium-55, clearly provide thermal protection to the hair, evicting damage [60]. ...
Cosmetics composed of synthetic and/or semi-synthetic polymers, associated or not with natural polymers, exhibit a dashing design, with thermal and chemo-sensitive properties. Cosmetic polymers are also used for the preparation of nanoparticles for the delivery of, e.g., fragrances, with the purpose to modify their release profile and also reducing the risk of evaporation. Besides, other cosmetically active nutrients, dermal permeation enhancers, have also been loaded into nanoparticles to improve their bioactivities on the skin. The use of natural polymers in cosmetic formulations is of particular relevance because of their biocompatible, safe, and eco-friendly character. These formulations are highly attractive and marketable to consumers, and are suitable for a plethora of applications, including make-up, skin, and hair care, and as modifiers and stabilizers. In this review, natural synthetic, semi-synthetic, and synthetic polymers are discussed considering their properties for cosmetic applications. Their uses in conventional and novel formulations are also presented.
... [27] Any damage to proteins may reduce water absorption and retention in hair; thus, altering the cosmetic appearance of hair. [32] Thus, it is quite likely that the same instrument at the same temperature and same procedure may have different effects on different hair types, and potentially, the damage may be higher in Asian hair. In our study, the prevalence of microscopic changes in women who had any hairstyling procedures in the past six months was very high 89%. ...
Background: The present study is a cross‑sectional comparison to evaluate the association between hair loss and hair structural changes (gross and microscopic), and hairstyling procedures in women. Methods: We included 94 women; and collected data on sociodemographics, clinical history, sun‑exposure, and hair‑product use history. Women who reported blow drying of hair, hair straightening, use of hair iron or perming in the past 6 months were classified as cases. Age matched (±2 years) women who did not report any of the above procedures in the past 6 months were controls. The following tests were done: hair pull test; hair density assessment; hair breakage index (HBI); and microscopic examination. A logistic regression model was used for estimation of the odds ratio (OR) and 95% confidence intervals (CI). Results: The mean (standard deviation [SD]) age in the case and control group was 26.4 (6.3) and 27.4 (6.3) years, respectively (P = 0.43). There was no significant difference in the mean (SD) HBI (1.05 [0.08] vs 1.07 [0.05], P = 0.22)
or hair density (3.28 [0.41] vs 3.16 [0.39], P = 0.19). Cases were significantly more likely to have microscopic changes compared with controls (OR: 22.0, 95% CI: 4.3, 112.6; P < 0.001). Sun exposure for more than 3 h was significantly associated with microscopic changes (OR: 6.7, 95% CI: 1.2, 39.1; P = 0.03). Conclusion: Women with hairstyling procedures in the past 6 months were more likely to have microscopic changes, even though there was no difference in the hair assessment parameters. Specific guidelines on use of hairstyling procedures for Indian hair should be developed.
... 9 Water alters the properties of human keratin fibres and, therefore, plays an important role in its cosmetic performance. 10 Dynamic vapour sorption (DVS) analysis can characterize the response of hair to humidity changes. The relationship between the equilibrium moisture content and relative humidity (RH) at a constant temperature is known as the sorption isotherm. ...
Background:
The aim of this study is to characterize and detect the possible differences among the hair of three different ethnicities: African, Asiatic and Caucasian.
Materials and methods:
The differences in water adsorption/desorption behaviour of hairs were studied using a thermogravimetric balance and compared with the analysis of the lipid distribution and order using synchrotron-based Fourier transform infrared microspectroscopy. Besides, the thermal thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses on human hair were executed.
Results:
Differences in the diffusion coefficients were evidenced. African hair exhibited increased permeability. Caucasian hair displayed a higher water absorption capability with increasing humidity but with a slow diffusion rate. The Asian fibre appeared to be more resistant to hydration changes. The spectroscopic analysis showed notable differences in the cuticle lipids. The African cuticle exhibited more lipids with a lower order bilayer. The outmost layer of Caucasian fibres contained more ordered lipids, and the Asian fibres show a very low level of lipids on the cuticle region. The DSC results indicate no difference in the thermal stability and TG showed higher water content in the Caucasian fibre and a possible lower cysteine disulphide bond content in the African hair matrix.
Conclusion:
The triple approach demonstrated the permeability differences among the ethnic fibres and their correlation with the properties of their cuticle lipids. These differences could have particular relevance to the hair care cosmetic market.
... Damage resulting from high temperature thermal styling treatments such as hot flat irons, blow dryers and curling irons has become an increasing concern in hair care. During these styling procedures the temperatures can exceed 200 • C, imparting significant damage to the hair keratin (Zhou et al., 2011). Since these styling appliances are known to cause significant damage to hair, there is a need for the development of thermal protective formulations capable to maintain the hair properties. ...
... The reduction of fibers' water content after iron application can be attributed to changes in protein conformation induced by extreme heat. It is already reported in the literature that the application of heating to keratin fibers induces a change in the keratin conformation, going from an α-helix structure to β-sheets (Watt, 1975;Zhou et al., 2011). The undamaged hair displays a well-organized structure based on α-helical coiled coil protein conformation, but, once the protein is exposed to high temperatures, it can unfold and convert into a β-sheet structure. ...
... The undamaged hair displays a well-organized structure based on α-helical coiled coil protein conformation, but, once the protein is exposed to high temperatures, it can unfold and convert into a β-sheet structure. These changes in protein conformation affect the hydrogen bonding structure that stabilizes the α-helical structure and, therefore, may change the water accessibility to the hair (Zhou et al., 2011). We can deduce that, when KP-Cryst Wt and KP-Cryst Mut are applied to the hair before iron application, the proteins reduce the heat flow from the source to the hair fiber, and subsequently reduce the water loss from the hair. ...
Styling hair with straightening irons is a popular daily hair routine that significantly damage the hair keratin fiber due to the high temperature applied. In this study, we investigate the effect of two fusion proteins based on the human eye γD-crystallin conjugated with a keratin-based peptide (KP-Cryst Wt and KP-Cryst Mut) on hair exposed to thermal damage. The mutant form was designed to improve protein stability and promote interaction with the hair. Through the study, it was demonstrated the protection of Asian and Caucasian virgin hair's structure by the pretreatments with the KP-Cryst fusion proteins. After hair thermal exposure, a higher water content was quantified by TGA on the hair fibers pretreated with the fusion proteins (about 38% for the KP-Cryst Wt and 44% for the KP-Cryst Mut). Also, negligible alterations in hair fibers' stiffness were observed after iron application, demonstrating the proteins capacity to effectively prevent the conversion of keratin α-helix structure into β-sheets. The results proved the capacity of the fusion proteins to bind to hair and protect it against high temperatures', supporting the development of new formulations based on the KP-Cryst proteins.
... Damage resulting from high temperature thermal styling treatments such as hot flat irons, blow dryers and curling irons has become an increasing concern in hair care. During these styling procedures the temperatures can exceed 200 • C, imparting significant damage to the hair keratin (Zhou et al., 2011). Since these styling appliances are known to cause significant damage to hair, there is a need for the development of thermal protective formulations capable to maintain the hair properties. ...
... The reduction of fibers' water content after iron application can be attributed to changes in protein conformation induced by extreme heat. It is already reported in the literature that the application of heating to keratin fibers induces a change in the keratin conformation, going from an α-helix structure to β-sheets (Watt, 1975;Zhou et al., 2011). The undamaged hair displays a well-organized structure based on α-helical coiled coil protein conformation, but, once the protein is exposed to high temperatures, it can unfold and convert into a β-sheet structure. ...
... The undamaged hair displays a well-organized structure based on α-helical coiled coil protein conformation, but, once the protein is exposed to high temperatures, it can unfold and convert into a β-sheet structure. These changes in protein conformation affect the hydrogen bonding structure that stabilizes the α-helical structure and, therefore, may change the water accessibility to the hair (Zhou et al., 2011). We can deduce that, when KP-Cryst Wt and KP-Cryst Mut are applied to the hair before iron application, the proteins reduce the heat flow from the source to the hair fiber, and subsequently reduce the water loss from the hair. ...
Styling hair with straightening irons is a popular daily hair routine that significantly damage
the hair keratin fiber due to the high temperature applied. In this study, we investigate
the effect of two fusion proteins based on the human eye gD-crystallin conjugated with
a keratin-based peptide (KP-Cryst Wt and KP-Cryst Mut) on hair exposed to thermal
damage. The mutant form was designed to improve protein stability and promote
interaction with the hair. Through the study, it was demonstrated the protection of Asian
and Caucasian virgin hair’s structure by the pretreatments with the KP-Cryst fusion
proteins. After hair thermal exposure, a higher water content was quantified by TGA
on the hair fibers pretreated with the fusion proteins (about 38% for the KP-Cryst Wt
and 44% for the KP-Cryst Mut). Also, negligible alterations in hair fibers’ stiffness were
observed after iron application, demonstrating the proteins capacity to effectively prevent
the conversion of keratin a-helix structure into b-sheets. The results proved the capacity
of the fusion proteins to bind to hair and protect it against high temperatures’, supporting
the development of new formulations based on the KP-Cryst proteins.
... The presence of the Amide III mode at 1248 cm −1 is attributed to the creation of a random protein coil structure; an increase in the intensity of this band is related to the modification of the α-helix secondary structure to an amorphous conformation, because when the protein is damaged, it converts into different protein chains, such as β-sheet and random coil, where these changes affect the structure of the hydrogen bonds that stabilize the helical structure [34]. This type of structural modification, caused by different treatments, has also been observed in investigations performed by Liu et al. [35] and Kuzuhara [36]. ...
Human hair fibre is subjected to various structural modifications due to the application of chemicals such as dyes, shampoos and bleaches and/or physical procedures such as heating, and often more than one procedure is performed on the same hair. The present work aims to analyze the changes incurred in hair samples of two ethnic groups, namely Caucasian and Afro, before and after different treatments such as thermal, bleaching and straightening. In addition to observing the damage caused by each treatment separately, the study of samples that received all three treatments was carried out. For molecular structural characterization , the Raman vibrational spectroscopic technique was used and scanning electron microscopy (SEM) was used for morphological analysis of the hair fibres. This investigation has shown, through vibrational spectroscopy, that several important bonds have been modified, such as the S-S, C-S, CC and SO bonds as well as the secondary structures of proteins that have indergone changes in their conformation as a result of the treatment. Hair from the two ethnic groups showed small differences in relation to each applied treatment. Excessive heat generated a higher rate of Raman spectral band intensity changes when compared to the other treatments and it was observed that the action of several treatments on the same hair fibres resulted in even more pronounced structural changes. Finally, scanning electron mi-croscopy showed that each treatment caused a different morphological deformation pattern on the capillary surface of the human hair.
