Title

Histological and wetting characterization of the superhydrophobic pistia stratiotes L. (water lettuce)

Date of Publication

2018

Document Type

Master's Thesis

Degree Name

Master of Science in Biology

College

College of Science

Department/Unit

Biology

Thesis Adviser

Jose Isagani B. Janairo

Defense Panel Member

Glenn V. Alea

Abstract/Summary

Pistia stratiotes, most commonly known as water lettuce, is a monospecies perennial monocotyledonous aquatic plant wherein it is considered as invasive species in most tropical and subtropical fresh watercourses in the Philippines. It has been reported to be a superhydrophobic plant which selectively absorbs oils while repelling water. Water lettuce has this selective wetting property which can potentially use to cleanup accidental oil spills while preventing secondary pollution in the environment and to develop bioinspired materials that require high water repellency and oil adsorbency. However, the surface morphological properties of the microstructures on the adaxial and abaxial surface of water lettuce and its interaction to water and common pure oils with increasing carbon chain length have not been well established. Consequently, the histology and surface morphology of the adaxial and abaxial surface of P. stratiotes leaves and its surface wetting properties towards deionized water and pure oil samples with varying carbon were characterized and compared with other hairy (S. molesta) and non-hairy (A. comosus and D. platyphylla) leaf surfaces. The surface morphological properties of P. stratiotes uniseriate trichomes on adaxial (ad) and abaxial (ab) surface involved length (ad1.26-2.39 mm; ab2.64-3.36 mm) and width (ad 0.10-0.34; ab0.19-0.43). Overall, P. stratiotes has the greatest trichome density (no.of trichomes/mm2) of ad 36.77 and ab40.10 among A. comosus (ad27.72; ab27.58) > D. platyphylla (ad 24.18; ab28.63) > S. molesta (ad8.26; ab7.15). Contact angle measurement showed that P. stratiotes has the best water repellency on the adaxial (154. 39 3.26) and abaxial (147.90 3.17) surface among the other three species wherein: on the adaxial surface, S. molesta (153.56 0.37) > A. comosus (52.01 4.96) > D. platyphylla (37.17 2.90); on the abaxial surface, A. comosus (130.61 4.33) > D. platyphylla (101.98 3.10) > S. molesta (42.04 4.55). Lastly, P. stratiotes showed the best common pure oil adsorption capacity than A. comosus, D. platyphylla and S. molesta. It was confirmed that oil density is directly proportional to oil adsorption onto the adaxial and abaxial surface of P. stratiotes. Therefore, the understanding on the fundamental concept on how the leaf surface of P. stratiotes adsorbs the oil and reacts in response to various solvents adsorbed on the leaf surface was established.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG007814

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer disc ; 4 3/4 in.

Keywords

Water lettuce

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