The most common example of a successful application of biomimetics in surface science is the Lotus Effect for water-repellency and self-cleaning. Among natural leaves, the lotus (Nelumbo nucifera) leaf exhibits extreme water repellence and hydrophobic behavior. When a water droplet is placed on a lotus leaf surface, the adhesion between the water and dust particles is greater than the adhesion between the dust and the leaf surface. As a result, the water droplet picks up the dust particles and rolls off the leaf surface immediately.
Lotus (पुण्डरीक Puṇḍarīka or पद्म Padma in Sanskrit, পুণ্ডরীক in Bengali, 蓮華 Liánhuá in Chinese) became a symbol of purity in many Asian cultures, as reflected in Hindu and Buddhist sacred texts such as the Bhagavat Gita 5:10 (“Having abandoned attachment they act unaffected by Evil, as Lotus leaf is not wetted”) or the Lotus Sutra 14:46 (“They have learned the bodhisattva way and are untainted by worldly things, just as the lotus flower in the water”).
Note that many different words are used for Lotus in Sanskrit. While the Lotus Sutra, a Mahāyāna Buddhist sacred text, is called Saddharma Puṇḍarīka Sūtra (“Sūtra on the White Lotus of the Sublime Dharma”), a more common word पद्म Padma is used in Bhagavat Gita 5:10, a Hindu sacred text:
ब्रह्मण्याधाय कर्माणि सङ्गं त्यक्त्वा करोति य:
लिप्यते न स पापेन पद्मपत्रमिवाम्भसा
brahmaṇyādhāya karmāṇi saṅgaṁ tyaktvā karoti yaḥ
lipyate na sa pāpena padma-patram ivāmbhasā
A literal translation: “Those who dedicate their actions to God, abandoning all attachment, remain untouched by sin, just as a lotus leaf is untouched by water.”
According to dictionaries, there are many dozens of other synonyms for the word “lotus” in Sanskrit: पद्म Padma, कुमुद Kumuda, पुष्कर Puṣkara, अम्भोजिनी Ambhojinī, पद्मिनी Padminī, पुण्डरीक Puṇḍarīka, उत्पल Utpala, दलकोमल Dalakomala, सरुद्भव Sarudbhava, तोयज Toyaja, मृणालिनी Mṛṇālinī, नलिनी Nalinī, अनीकिनी Anīkinī, जलजा Jalajā, उत्पलिनी Utpalinī, अम्बुरुहिणी Amburuhiṇī, सूक Sūka, श्रीवास Śrīvāsa, मदनार्णव Madanārṇava, गम्भीर Gambhīra, वारिज Vārija, पर्णसि Parṇasi, नीरज Nīraja, सहस्रपत्त्र Sahasrapattra, अम्बुज Ambuja, आस्यपत्त्र Āsyapattra,शृङ्ग Śṛṅga, पाथोज Pāthoja, नदीज Nadīja, सरोजन्मन् Sarojanman, उदज Udaja, सरसिरुह Sarasiruha, कुटप Kuṭapa, विष्णुपद Viṣṇupada, अरविन्द Aravinda, सरोज Saroja, सरसिज Sarasija, नलिन Nalina, जलाह्वय Jalāhvaya, सरसीज Sarasīja, नीररुह Nīraruha, कवार Kavāra, कमल Kamala, सलिलजन्मन् Salilajanman, अम्भोरुह् Ambhoruh, पाथोरुह Pāthoruha, पङ्कज Paṅkaja, हिम Hima, सुजल Sujala, कञ्ज Kañja, खरदण्ड Kharadaṇḍa, अम्भोजन्मन् Abhojanman, पन्ङ्कज Panṅkaja, कुव Kuva, दृशाकाङ्क्ष्य Dṛśākāṅkṣya, कज Kaja, शीतल Śītala, कान्तार Kāntāra, श्रीपर्ण Śrīparṇa, जलेजात Jalejāta, शोभन Śobhana, पयोरुह Payoruha, जलजकुसुम Jalajakusuma, देवन Devana, सरसीरुह् Sarasīruh, सारस Sārasa, रमाप्रिय Ramāpriya, अम्बुजन्मन् Ambujanman, हिमाह्वय Himāhvaya, सरोरुह् Saroruh, जलजन्मन् Jalajanman.
This folio of the popular Saddharmapuṇḍarīkasūtra (Lotus Sutra) is written in Sanskrit in an early form of South Turkestan Brahmi script (from Wikipedia).
Lotus (sidr[un] ﺳﺪﺮ) is also mentioned as a symbol of purity in the Quran (Al-Waqi‘ah 56:28) and in the Hadith (The Book of Purification 1:189). This is the term which is used in the Quran when it talks about the future destination of the righteous in Paradise:
فِي سِدْرٍ مَخْضُودٍ
“[They will be] among lote trees with thorns removed”
Lotus leaves (Sidr) as a means of purification is also mentioned in the Hadith (The Book of Purification 1:189)
أَنْ يَغْتَسِلَ بِمَاءٍ وَسِدْرٍ
“[Prophet commanded him] to perform purification with water and lotus leaves.”
However, this lotus is not the same as the lotus of India. The word “lotus” referred to many different plants including Nelumbo (a genus of aquatic plants with showy flowers) and Nymphaea (water lilies or Egyptian lotuses):
- Nelumbo nucifera, (the Sacred Indian lotus)
- Nelumbo lutea (the American or Yellow lotus)
- Nymphaea caerulea (the blue lotus)
- Nymphaea lotus (white lotus or sacred lotus)
- Nymphaea nouchali (blue or star lotus)
- Saussurea (snow lotus)
- Ziziphus lotus (a shrub species with edible fruit)
- Diospyros lotus (date-plum, Caucasian persimmon, a tree with edible fruit)
Nelumbo nucifera (the Sacred or Indian lotus (from Wikipedia)
Nymphaea lotus Egyptian white lotus or water lily (from Wikipedia)
Ziziphus lotus (from Wikipedia)
The Ziziphus lotus, which is a shrub or a small tree, was called the “Lote Tree” (sidr) in the Quran. It is likely that the same plant, the Lotus (λωτός), was also mentioned in Greek mythology (Homer’s Odyssey) as a tree bearing a fruit that caused a pleasant drowsiness. The lotus was the only available food of an island inhabited by people called the Lotophagi λωτοφάγοι (Lotus-eaters). After eating the lotus, they would forget their friends and homes.
Apparently, the Lotus Trees are mentioned once in the Hebrew Bible in the Book of Job (40:21-22), where they are called צֶאֱלִים (tse’elim),
Finally, Nymphaea lotus (the white Egyptian lotus or water lily) was worshipped in Ancient Egypt. This flower often appeared in ancient Egyptian decorations. Moreover, the number 1,000 was represented by the symbol of the white lotus: 𓆼 .
Returning to the question in the title of this article, it was Nelumbo nucifera, the Sacred or Indian lotus, after which the famous Lotus-Effect was called.