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A facile methodology to make the glass surface superhydrophobic
Materials Letters 264 (2020) 127347
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
A facile methodology to make the glass surface superhydrophobic Nidchamon Jumrus a,b, Thanakorn Chaisen b, Atchara Sriboonruang d, Arisara Panthawan a,b,d, Tewasin Kumpika d, Ekkapong Kantarak b, Pisith Singjai b,c,d, Wiradej Thongsuwan b,c,d,⇑ a
The Graduate School in Chiang Mai University (GSCMU), Chiang Mai 50200, Thailand Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand c Center of Advanced Materials of Printed Electronics and Sensors, Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand d Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand b
a r t i c l e
i n f o
Article history: Received 19 November 2019 Received in revised form 20 December 2019 Accepted 11 January 2020 Available online 13 January 2020 Keywords: Superhydrophobic Annealing Etching Hydrofluoric acid Methyltrichlorosilane
a b s t r a c t In this work, the glass surface was successfully modified via low-temperature annealing and wet etching techniques. Hydrophilic/superhydrophobic of the modified glass surface was then transformed after dipped with methyltrichlorosilane (MTCS). Morphology and structural properties of the samples were analyzed by scanning electron microscopy, atomic force microscopy, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results exhibit that micro/nano roughness was observed on the annealed/etched glass surface. Interestingly, the wettability of the annealed and etched glass abruptly transformed to superhydrophobic with a water contact angle of 154° and a sliding angle of 3° after coating with MTCS. Annealing assisted etching technique not only plays an important role in changing of roughness in nanoscale by reducing residual and hardness but also changes the formation of polysiloxane from microspheres to nanofilaments on the surface. Ó 2020 Elsevier B.V. All rights reserved.
1. Introduction Superhydrophobic phenomena are often found in nature, for example, lotus leaf, due to its high-water contact angle and low roll-off angle [1]. In general, the wettability of a surface is dependent on surface roughness and surface energy, which can be described by the Wenzel and Cassie-Baxter models [2] as follows:
Wenzel equation; cos hw e ¼ r cos he
ð1Þ
Cassie-Baxter equation; cos hCe ¼ us ðcos he Þ þ ð1 us Þ cos hX
ð2Þ
Although, many researches have been coated nanoparticles/ films on glass using some techniques [3,4]. Their coating easily destroyed due to weak physical or chemical bonding between the coating and substrate, leading to loss of superhydrophobicity [5]. Recently, Meng Xu at el. have been focused on the fabrication of superhydrophobic surfaces using wet chemical etching processes [6]. Hydrofluoric acid (HF) etching can permanently improve the surface roughness due to simple, high etching rate and low-cost method. However, the limitation of wet chemical ⇑ Corresponding author at: Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. E-mail address: [email protected] (W. Thongsuwan). https://doi.org/10.1016/j.matlet.2020.127347 0167-577X/Ó 2020 Elsevier B.V. All rights reserved.
etching is uncontrolled in the reaction and the roughness in microscale [7]. Although it could increase the water contact angle followed by the Wenzel model, it could not demonstrate a low sliding angle followed by the Cassie-Baxter model. Therefore, a simple and cost-effective method to fabricate surfaces in nanoroughness remains a challenge, because surface roughness directly affected to hydrophilic –OH groups. Annealing process plays an important role in the changes in physical characteristics, such as glass crystallization, residual stress, strengths, thermal expansion, and hardness. Since it occurs at a lower temperature lower than the transition point [8,9]. The combination of annealing and etching processes has been successfully applied to construct the superhydrophobicity to Cassie-Baxter models [6]. However, no research has focused on soda-lime silicate glass due to its low transition temperature, despite soda-lime silicate glass is the most important commercial glass with many applications [10]. In addition to surface roughness being an important factor, low surface energy also contributes to superhydrophobicity. Methlytrichlorosilane (MTCS) in particular has more chemical reactivity than others in the alkyltrichlorosilane group [11]. In this work, we aim to build on previous findings to solve common problems and improve the simple and cost-effective methods for imparting superhydrophobic properties on low-temperature glass surfaces. Simple annealing and etching techniques were used to increase the surface roughness of glass. The etched/annealed
2
N. Jumrus et al. / Materials Letters 264 (2020) 127347
Fig. 1. SEM and AFM images of sample G (A and a), GA (B and b), GE (C and c) and (D and d) GAE without MTCS.
Fig. 2. XPS spectra of O 1s for sample G (a), GA (b), GE (c) and GAE (d) without MTCS.
N. Jumrus et al. / Materials Letters 264 (2020) 127347
glass was then made superhydrophobic by dip-coating in Methlytrichlorosilane (MTCS). 2. Experimental details 2.1. Samples preparation Glass surfaces were modified to be hydrophilic by cleaning microscope glass slides (10 30 1 mm3, SAIL BRAND,
3
transition temperature 545 °C). Four conditions were tested in this research: bare glass slides (G), annealed glass at 100 °C for 1 h under atmospheric pressure (GA), etched glass with 6% v/v concentration of hydrofluoric acid (HF, 48% purity, EMSUEÒ) (GE), annealed and etched glass (GAE). MTCS solution with a concentration of 2.5% v/v (99% purity, Sigma-Aldrich) in toluene (99.5% purity, RCI Labscan Limited) was used as a precursor. The precursor solution was coated on all samples using a dip-coating technique for 1 h.
Fig. 3. SEM images of sample (a) G, (b) GA, (c) GE, (d) GAE after coated with MTCS, (e) Formation mechanism of polysiloxane spheres and (f) polysiloxane nanofilaments.
4
N. Jumrus et al. / Materials Letters 264 (2020) 127347
2.2. Sample characterization Surface morphology and chemical composition of samples were characterized by scanning electron microscopy (SEM, JEOL JSM 6335F), atomic force microscopy (AFM, Digital Instruments, Inc.), X-ray photoelectron spectroscopy (XPS, AXIS ULTRADLD, Kratos analytical, Manchester, UK.) and fourier transform infrared spectroscopy (FT-IR, Bruker, TENSOR 27). The mean roughness (Ra) of samples can be calculated by using AFM in roughness analysis mode. Wettability (water contact angle; WCA and sliding angle; SA) was evaluated using a pendant drop tensiometer. WCA and SA were measured at five different areas for each sample with a 3 mL of water droplet under ambient temperature. 3. Results and discussion Fig. 1(A, a) shows the microstructures of bare glass (sample G) with the mean roughness (Ra) of 0.21 nm. After annealing at 100 °C (Fig. 1(B, b)), the roughness was increased to 10.45 nm. It is worth noting that the annealing temperature has directly affected the thermal expansion, residual stress, and hardness leading to the change in nano-scale on the glass [9]. After etching, the roughness of sample GE (Fig. 1(C, c) was 53.98 nm, while the roughness of sample GAE (Fig. 1(D, d)) slightly decreased to 42.90 nm. After annealing, the overflow of oxides onto the surface form protrusions [8]. Moreover, the hardness of sample G decreases from 402.1 to 309.1 HV (sample GA). The germination of submicron particles on the surface (see Fig. 1(b)) and decreasing hardness after annealing plays a role in initial etching. This is a major factor in the modification of glass surfaces by using coupling techniques. Fig. 2 shows the binding energy of O 1s. The three fitted peaks correspond to –OH, Si–O–Si [12], and Na KLL bonding [13]. The peak of –OH is indicated by the number of hydroxyl groups on the surface, which directly affected the wettability. From the results, the GE and GAE samples show high –OH value due to the increasing roughness.
Fig. 3 shows the different morphologies and the magnification (inset) of samples after being coated with MTCS. The G sample shows polysiloxane spheres of size 87–521 nm. For the GA and GE samples, different sizes of polysiloxane with small grains in the range of 174–1043 nm and short nanofilaments were grafted on the surface. Interestingly, the films of polysiloxane nanofilaments with a diameter in the range of 25–73 nm were covered on the GAE sample. It is clearly seen that the formation of polysiloxane depends on the roughness and presence of hydroxyl groups. The grafting mechanism of polysiloxane on different surfaces is shown in Fig. 3(e and f). The surface morphology and hydroxyl groups present on the silica surface (Si–OH) of the glass slide play an important role in determining the formation of Si–O–Si linkages. Thus, self-assembly to form polysiloxane spheres easily occurred on the flat surface due to low –OH. On the other hand, the rough surface has highly reactive on the surface and leads to the formation of polysiloxane nanofilaments [14]. The chemical composition of samples was observed using FT-IR, as shown in Fig. 4(a). The results show the asymmetric stretching of the –CH3 group and Si-CH3 deformation vibration of the MTCS molecules. The results confirmed the chemical grafting of MTCS which can reduce the Si–OH peak [15,16]. The wettability of samples without MTCS is shown in Fig. 4(b). This could indicate that surface roughness has a direct effect on WCA. After coated with MTCS, the wettability indicated a clear and rapid change from hydrophilic to hydrophobic behavior. Interestingly, the GAE sample exhibited superhydrophobic behavior with WCA of 154° and SA of 3°. Although the surface roughness of sample GAE is less than sample GE, WCA of sample GAE is greater than that of GE. Because the roughness of sample GAE is in the nano-scale, whereas the roughness of GE is in the micro-scale. It can be concluded that surface roughness in the nano-scale is an important factor for increase WCA. Moreover, the surface morphology of GAE consisted of nanofilaments (see Fig. 3(d)), which corresponded to the Cassie-Baxter state. Whereas the G, GE, and GA samples had high WCA but water droplets could
Fig. 4. (a) FT-IR spectra of samples after coated with MTCS, (b) WCA of the samples without and with MTCS and SA of samples coated with MTCS and (c) The actual photograph of water droplets on the sample GAE.
N. Jumrus et al. / Materials Letters 264 (2020) 127347
5
not roll-off. These results corresponded to the Wenzel state, in which the adhesive force between the droplet and surface is very high [11]. This result is in good agreement with Khoo and Tseng [14]. The WCA not only depends on surface roughness but also on the morphology of roughness and surface hydroxyl groups. Thus, surface modification of low-temperature glass slides using annealing and etching techniques can improve the surface roughness at the nano-scale and high hydroxyl groups. This is an advantage for the surface, as it leads to the excellent superhydrophobic.
Acknowledgements
4. Conclusions
[1] A.B. Gurav, Q. Xu, S.S. Latthe, R.S. Vhatkar, S. Liu, H. Yoo, S.S. Yoo, Ceram. Int. 41 (2015) 3017–3023, https://doi.org/10.1016/j.ceramint.2014.10.137. [2] H.M. Shang, Y. Wang, S.J. Limmer, T.P. Chou, K. Takahashi, G.Z. Cao, Thin Solid Films 472 (2005) 37–43. [3] L. Peng, Y. Meng, H. Li, Cellulose 23 (2016) 2073–2085. [4] N.J. Shirtcliffe, G. McHale, M.I. Newton, G. Chabrol, C.C. Perry, Adv. Mater. 16 (21) (2004) 1929–1932, https://doi.org/10.1002/adma.200400315. [5] X. Men, Z. Zhang, J. Yang, X. Zhu, K. Wang, W. Jiang, New J Chem. 35 (2011) 881–886, https://doi.org/10.1039/C0NJ00954G. [6] M. Xu, Y. Feng, Z. Li, X. Wang, C. Li, H. Jiang, Y. Chen, J. Alloys Compd. 781 (2019) 1175–1181, https://doi.org/10.1016/j.jallcom.2018.12.084. [7] H. Park, J.H. Cho, J.H. Jung, P.P. Duy, A.H. Tuan Le, J. Yi, Curr. Photovoltaic Res. 5 (3) (2017) 75–82, https://doi.org/10.21218/CPR.2017.5.3.075. [8] D. Zhang, N. Gao, W. Yan, W. Luo, L. Zhang, C. Zhao, W. Zhang, D. Liu, Mater. Lett. 223 (2018) 1–4, https://doi.org/10.1016/j.matlet.2018.03.158. [9] M.D. Michel, A. Mikowski, C.M. Lepienski, C.E. Foerster, F.C. Serbena, J. Non-Cryst. Solids 348 (2004) 131–138, https://doi.org/10.1016/j.jnoncrysol. 2004.08.138. [10] S.S. Latthe, A.B. Gurav, C.S. Maruti, R.S. Vhatkar, J. Surf. Eng. Mater. Adv. Technol. 2 (2012) 76–94, https://doi.org/10.4236/jsemat.2012.22014. [11] E.G. Atici, E. Kasapgil, I. Anac, H. YildirimErbil, Thin Solid Films. 616 (2016) 101–110, https://doi.org/10.1016/j.tsf.2016.07.041. [12] S. He, Y. Huang, G. Chen, M. Feng, H. Dai, B. Yuan, X. Chen, Hazard Mater. (2018), https://doi.org/10.1016/j.jhazmat.2018.08.087. [13] A. Mekki, J. Electron. Spect. Related Phen. 142 (2005) 75–81, https://doi.org/ 10.1016/j.elspec.2004.09.001. [14] H.S. Khoo, F.G. Tseng, Nanotechnology 19 (2008), https://doi.org/10.1088/ 0957- 4484/19/34/345603 345603. [15] A. Sriboonruang, T. Kumpika, E. Kantarak, W. Sroila, P. Singjai, N. Lawan, S. Muangpil, W. Thongsuwan, Mater. Lett. 248 (2019) 227–230, https://doi.org/ 10.1016/j.matlet.2019.04.047. [16] J. Saha, K. Bhowmik, I. Das, G. De, Dalton Trans. 43 (35) (2014) 13325–13332, https://doi.org/10.1039/c4dt01438c.
In summary, the glass surface was successfully modified using facile annealing and etching techniques. The annealing temperature not only reduces the residual stress but also reduces the hardness on the glass surface. Surface morphology and hydroxyl groups are the key points for controlling the morphology of the MTCS polysiloxane. Finally, surface roughness at different scales not only affects the formation of polysiloxane but also affects the superhydrophobicity following the Wenzel and Cassie-Baxter models. CRediT authorship contribution statement Nidchamon Jumrus: Conceptualization, Methodology, Visualization, Formal analysis, Data curation, Writing - original draft. Thanakorn Chaisen: Conceptualization, Visualization, Methodology. Atchara Sriboonruang: Validation. Arisara Panthawan: Validation. Tewasin Kumpika: Validation. Ekkapong Kantarak: Methodology. Pisith Singjai: Resources, Investigation. Wiradej Thongsuwan: Conceptualization, Visualization, Formal analysis, Writing - review & editing. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
This work was supported by The Science Achievement Scholarship of Thailand, The Graduate School Chiang Mai, Center of Advanced Materials for Printed Electronics and Sensors Materials Science Research Center and Department of Physics and Materials Science, Faculty of Science, Chiang Mai University. References
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
A facile methodology to make the glass surface superhydrophobic Nidchamon Jumrus a,b, Thanakorn Chaisen b, Atchara Sriboonruang d, Arisara Panthawan a,b,d, Tewasin Kumpika d, Ekkapong Kantarak b, Pisith Singjai b,c,d, Wiradej Thongsuwan b,c,d,⇑ a
The Graduate School in Chiang Mai University (GSCMU), Chiang Mai 50200, Thailand Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand c Center of Advanced Materials of Printed Electronics and Sensors, Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand d Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand b
a r t i c l e
i n f o
Article history: Received 19 November 2019 Received in revised form 20 December 2019 Accepted 11 January 2020 Available online 13 January 2020 Keywords: Superhydrophobic Annealing Etching Hydrofluoric acid Methyltrichlorosilane
a b s t r a c t In this work, the glass surface was successfully modified via low-temperature annealing and wet etching techniques. Hydrophilic/superhydrophobic of the modified glass surface was then transformed after dipped with methyltrichlorosilane (MTCS). Morphology and structural properties of the samples were analyzed by scanning electron microscopy, atomic force microscopy, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results exhibit that micro/nano roughness was observed on the annealed/etched glass surface. Interestingly, the wettability of the annealed and etched glass abruptly transformed to superhydrophobic with a water contact angle of 154° and a sliding angle of 3° after coating with MTCS. Annealing assisted etching technique not only plays an important role in changing of roughness in nanoscale by reducing residual and hardness but also changes the formation of polysiloxane from microspheres to nanofilaments on the surface. Ó 2020 Elsevier B.V. All rights reserved.
1. Introduction Superhydrophobic phenomena are often found in nature, for example, lotus leaf, due to its high-water contact angle and low roll-off angle [1]. In general, the wettability of a surface is dependent on surface roughness and surface energy, which can be described by the Wenzel and Cassie-Baxter models [2] as follows:
Wenzel equation; cos hw e ¼ r cos he
ð1Þ
Cassie-Baxter equation; cos hCe ¼ us ðcos he Þ þ ð1 us Þ cos hX
ð2Þ
Although, many researches have been coated nanoparticles/ films on glass using some techniques [3,4]. Their coating easily destroyed due to weak physical or chemical bonding between the coating and substrate, leading to loss of superhydrophobicity [5]. Recently, Meng Xu at el. have been focused on the fabrication of superhydrophobic surfaces using wet chemical etching processes [6]. Hydrofluoric acid (HF) etching can permanently improve the surface roughness due to simple, high etching rate and low-cost method. However, the limitation of wet chemical ⇑ Corresponding author at: Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. E-mail address: [email protected] (W. Thongsuwan). https://doi.org/10.1016/j.matlet.2020.127347 0167-577X/Ó 2020 Elsevier B.V. All rights reserved.
etching is uncontrolled in the reaction and the roughness in microscale [7]. Although it could increase the water contact angle followed by the Wenzel model, it could not demonstrate a low sliding angle followed by the Cassie-Baxter model. Therefore, a simple and cost-effective method to fabricate surfaces in nanoroughness remains a challenge, because surface roughness directly affected to hydrophilic –OH groups. Annealing process plays an important role in the changes in physical characteristics, such as glass crystallization, residual stress, strengths, thermal expansion, and hardness. Since it occurs at a lower temperature lower than the transition point [8,9]. The combination of annealing and etching processes has been successfully applied to construct the superhydrophobicity to Cassie-Baxter models [6]. However, no research has focused on soda-lime silicate glass due to its low transition temperature, despite soda-lime silicate glass is the most important commercial glass with many applications [10]. In addition to surface roughness being an important factor, low surface energy also contributes to superhydrophobicity. Methlytrichlorosilane (MTCS) in particular has more chemical reactivity than others in the alkyltrichlorosilane group [11]. In this work, we aim to build on previous findings to solve common problems and improve the simple and cost-effective methods for imparting superhydrophobic properties on low-temperature glass surfaces. Simple annealing and etching techniques were used to increase the surface roughness of glass. The etched/annealed
2
N. Jumrus et al. / Materials Letters 264 (2020) 127347
Fig. 1. SEM and AFM images of sample G (A and a), GA (B and b), GE (C and c) and (D and d) GAE without MTCS.
Fig. 2. XPS spectra of O 1s for sample G (a), GA (b), GE (c) and GAE (d) without MTCS.
N. Jumrus et al. / Materials Letters 264 (2020) 127347
glass was then made superhydrophobic by dip-coating in Methlytrichlorosilane (MTCS). 2. Experimental details 2.1. Samples preparation Glass surfaces were modified to be hydrophilic by cleaning microscope glass slides (10 30 1 mm3, SAIL BRAND,
3
transition temperature 545 °C). Four conditions were tested in this research: bare glass slides (G), annealed glass at 100 °C for 1 h under atmospheric pressure (GA), etched glass with 6% v/v concentration of hydrofluoric acid (HF, 48% purity, EMSUEÒ) (GE), annealed and etched glass (GAE). MTCS solution with a concentration of 2.5% v/v (99% purity, Sigma-Aldrich) in toluene (99.5% purity, RCI Labscan Limited) was used as a precursor. The precursor solution was coated on all samples using a dip-coating technique for 1 h.
Fig. 3. SEM images of sample (a) G, (b) GA, (c) GE, (d) GAE after coated with MTCS, (e) Formation mechanism of polysiloxane spheres and (f) polysiloxane nanofilaments.
4
N. Jumrus et al. / Materials Letters 264 (2020) 127347
2.2. Sample characterization Surface morphology and chemical composition of samples were characterized by scanning electron microscopy (SEM, JEOL JSM 6335F), atomic force microscopy (AFM, Digital Instruments, Inc.), X-ray photoelectron spectroscopy (XPS, AXIS ULTRADLD, Kratos analytical, Manchester, UK.) and fourier transform infrared spectroscopy (FT-IR, Bruker, TENSOR 27). The mean roughness (Ra) of samples can be calculated by using AFM in roughness analysis mode. Wettability (water contact angle; WCA and sliding angle; SA) was evaluated using a pendant drop tensiometer. WCA and SA were measured at five different areas for each sample with a 3 mL of water droplet under ambient temperature. 3. Results and discussion Fig. 1(A, a) shows the microstructures of bare glass (sample G) with the mean roughness (Ra) of 0.21 nm. After annealing at 100 °C (Fig. 1(B, b)), the roughness was increased to 10.45 nm. It is worth noting that the annealing temperature has directly affected the thermal expansion, residual stress, and hardness leading to the change in nano-scale on the glass [9]. After etching, the roughness of sample GE (Fig. 1(C, c) was 53.98 nm, while the roughness of sample GAE (Fig. 1(D, d)) slightly decreased to 42.90 nm. After annealing, the overflow of oxides onto the surface form protrusions [8]. Moreover, the hardness of sample G decreases from 402.1 to 309.1 HV (sample GA). The germination of submicron particles on the surface (see Fig. 1(b)) and decreasing hardness after annealing plays a role in initial etching. This is a major factor in the modification of glass surfaces by using coupling techniques. Fig. 2 shows the binding energy of O 1s. The three fitted peaks correspond to –OH, Si–O–Si [12], and Na KLL bonding [13]. The peak of –OH is indicated by the number of hydroxyl groups on the surface, which directly affected the wettability. From the results, the GE and GAE samples show high –OH value due to the increasing roughness.
Fig. 3 shows the different morphologies and the magnification (inset) of samples after being coated with MTCS. The G sample shows polysiloxane spheres of size 87–521 nm. For the GA and GE samples, different sizes of polysiloxane with small grains in the range of 174–1043 nm and short nanofilaments were grafted on the surface. Interestingly, the films of polysiloxane nanofilaments with a diameter in the range of 25–73 nm were covered on the GAE sample. It is clearly seen that the formation of polysiloxane depends on the roughness and presence of hydroxyl groups. The grafting mechanism of polysiloxane on different surfaces is shown in Fig. 3(e and f). The surface morphology and hydroxyl groups present on the silica surface (Si–OH) of the glass slide play an important role in determining the formation of Si–O–Si linkages. Thus, self-assembly to form polysiloxane spheres easily occurred on the flat surface due to low –OH. On the other hand, the rough surface has highly reactive on the surface and leads to the formation of polysiloxane nanofilaments [14]. The chemical composition of samples was observed using FT-IR, as shown in Fig. 4(a). The results show the asymmetric stretching of the –CH3 group and Si-CH3 deformation vibration of the MTCS molecules. The results confirmed the chemical grafting of MTCS which can reduce the Si–OH peak [15,16]. The wettability of samples without MTCS is shown in Fig. 4(b). This could indicate that surface roughness has a direct effect on WCA. After coated with MTCS, the wettability indicated a clear and rapid change from hydrophilic to hydrophobic behavior. Interestingly, the GAE sample exhibited superhydrophobic behavior with WCA of 154° and SA of 3°. Although the surface roughness of sample GAE is less than sample GE, WCA of sample GAE is greater than that of GE. Because the roughness of sample GAE is in the nano-scale, whereas the roughness of GE is in the micro-scale. It can be concluded that surface roughness in the nano-scale is an important factor for increase WCA. Moreover, the surface morphology of GAE consisted of nanofilaments (see Fig. 3(d)), which corresponded to the Cassie-Baxter state. Whereas the G, GE, and GA samples had high WCA but water droplets could
Fig. 4. (a) FT-IR spectra of samples after coated with MTCS, (b) WCA of the samples without and with MTCS and SA of samples coated with MTCS and (c) The actual photograph of water droplets on the sample GAE.
N. Jumrus et al. / Materials Letters 264 (2020) 127347
5
not roll-off. These results corresponded to the Wenzel state, in which the adhesive force between the droplet and surface is very high [11]. This result is in good agreement with Khoo and Tseng [14]. The WCA not only depends on surface roughness but also on the morphology of roughness and surface hydroxyl groups. Thus, surface modification of low-temperature glass slides using annealing and etching techniques can improve the surface roughness at the nano-scale and high hydroxyl groups. This is an advantage for the surface, as it leads to the excellent superhydrophobic.
Acknowledgements
4. Conclusions
[1] A.B. Gurav, Q. Xu, S.S. Latthe, R.S. Vhatkar, S. Liu, H. Yoo, S.S. Yoo, Ceram. Int. 41 (2015) 3017–3023, https://doi.org/10.1016/j.ceramint.2014.10.137. [2] H.M. Shang, Y. Wang, S.J. Limmer, T.P. Chou, K. Takahashi, G.Z. Cao, Thin Solid Films 472 (2005) 37–43. [3] L. Peng, Y. Meng, H. Li, Cellulose 23 (2016) 2073–2085. [4] N.J. Shirtcliffe, G. McHale, M.I. Newton, G. Chabrol, C.C. Perry, Adv. Mater. 16 (21) (2004) 1929–1932, https://doi.org/10.1002/adma.200400315. [5] X. Men, Z. Zhang, J. Yang, X. Zhu, K. Wang, W. Jiang, New J Chem. 35 (2011) 881–886, https://doi.org/10.1039/C0NJ00954G. [6] M. Xu, Y. Feng, Z. Li, X. Wang, C. Li, H. Jiang, Y. Chen, J. Alloys Compd. 781 (2019) 1175–1181, https://doi.org/10.1016/j.jallcom.2018.12.084. [7] H. Park, J.H. Cho, J.H. Jung, P.P. Duy, A.H. Tuan Le, J. Yi, Curr. Photovoltaic Res. 5 (3) (2017) 75–82, https://doi.org/10.21218/CPR.2017.5.3.075. [8] D. Zhang, N. Gao, W. Yan, W. Luo, L. Zhang, C. Zhao, W. Zhang, D. Liu, Mater. Lett. 223 (2018) 1–4, https://doi.org/10.1016/j.matlet.2018.03.158. [9] M.D. Michel, A. Mikowski, C.M. Lepienski, C.E. Foerster, F.C. Serbena, J. Non-Cryst. Solids 348 (2004) 131–138, https://doi.org/10.1016/j.jnoncrysol. 2004.08.138. [10] S.S. Latthe, A.B. Gurav, C.S. Maruti, R.S. Vhatkar, J. Surf. Eng. Mater. Adv. Technol. 2 (2012) 76–94, https://doi.org/10.4236/jsemat.2012.22014. [11] E.G. Atici, E. Kasapgil, I. Anac, H. YildirimErbil, Thin Solid Films. 616 (2016) 101–110, https://doi.org/10.1016/j.tsf.2016.07.041. [12] S. He, Y. Huang, G. Chen, M. Feng, H. Dai, B. Yuan, X. Chen, Hazard Mater. (2018), https://doi.org/10.1016/j.jhazmat.2018.08.087. [13] A. Mekki, J. Electron. Spect. Related Phen. 142 (2005) 75–81, https://doi.org/ 10.1016/j.elspec.2004.09.001. [14] H.S. Khoo, F.G. Tseng, Nanotechnology 19 (2008), https://doi.org/10.1088/ 0957- 4484/19/34/345603 345603. [15] A. Sriboonruang, T. Kumpika, E. Kantarak, W. Sroila, P. Singjai, N. Lawan, S. Muangpil, W. Thongsuwan, Mater. Lett. 248 (2019) 227–230, https://doi.org/ 10.1016/j.matlet.2019.04.047. [16] J. Saha, K. Bhowmik, I. Das, G. De, Dalton Trans. 43 (35) (2014) 13325–13332, https://doi.org/10.1039/c4dt01438c.
In summary, the glass surface was successfully modified using facile annealing and etching techniques. The annealing temperature not only reduces the residual stress but also reduces the hardness on the glass surface. Surface morphology and hydroxyl groups are the key points for controlling the morphology of the MTCS polysiloxane. Finally, surface roughness at different scales not only affects the formation of polysiloxane but also affects the superhydrophobicity following the Wenzel and Cassie-Baxter models. CRediT authorship contribution statement Nidchamon Jumrus: Conceptualization, Methodology, Visualization, Formal analysis, Data curation, Writing - original draft. Thanakorn Chaisen: Conceptualization, Visualization, Methodology. Atchara Sriboonruang: Validation. Arisara Panthawan: Validation. Tewasin Kumpika: Validation. Ekkapong Kantarak: Methodology. Pisith Singjai: Resources, Investigation. Wiradej Thongsuwan: Conceptualization, Visualization, Formal analysis, Writing - review & editing. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
This work was supported by The Science Achievement Scholarship of Thailand, The Graduate School Chiang Mai, Center of Advanced Materials for Printed Electronics and Sensors Materials Science Research Center and Department of Physics and Materials Science, Faculty of Science, Chiang Mai University. References