Tunable Wettability Research Articles

Synthesis, characterization, and optical sensing of hydrophilic anodic alumina films

Herein, the anodization of 2.6 μm Al-0.2 at. % Cu (Al-0.2Cu) films on TiN/p-type Si substrate were performed using common acidic mediums at different ranges of anodization voltage (Va) to produce porous anodic alumina (PAA) nanostructures with high porosity. The anodization of Al-0.2Cu in 1 M H2SO4 at Va range of 10–30 V produced a higher oxide thickness, and hence, a higher volume expansion factor, compared to the anodization in 0.75 M H3PO4 at Va range of 100–140 V. The increase in Va, as expected, increases the inter-pore distance, pore size, and porosity of the PAA and improves the anodization rate. The optical sensing performance of the synthesized PAA under different conditions was investigated. The maximum surface wettability was attained for PAA anodized in 1 M H2SO4 at 20 and 30 V. Moreover, the Vickers hardness (HV) of PAA was improved by forming a thin alumina layer on the Al-0.2Cu surface, and the anodized Al-0.2Cu in 0.3 M C2H2O4 revealed the highest HV compared to other acids. The synthesized PAA was tested as an optical sensor for some liquids by monitoring the refractive index. The synthesized PAA structure demonstrated a sensitivity of 180 nm/RIU. The anodization of Al-0.2Cu films using a one-step anodization process in different acidic mediums, and the resulting multifunctional properties (improved hardness, tunable wettability, and competitive sensitivity) existing a novel and potentially impactful approach.

Physicochemically modified polymer-based fluidic gates with tunable wetting properties for intelligent liquid manipulations

The creation of a selective flow path and the regulation of a flow rate are of critical importance for polymer-based devices that manipulate liquid at the microscale. The formation of a 3D interconnected network of voids (i.e., physical volumetric modification) and the addition of a nonionic surfactant, Silwet L-77, (i.e., chemical volumetric modification) are expected to affect the wetting properties of polymers, thereby achieving selective gating effect in the polymer-based devices as an appropriate technology. Here, a set of polydimethylsiloxane (PDMS)-based fluidic gates (F-gates) were developed to enable selectivity for liquids and flow-rate control of the liquids by tuning the wetting properties of PDMS with the physicochemical volumetric modifications. For water and oil with different surface tensions (STs), the effects of the physical and chemical volumetric modifications on the fluidic gating of PDMS were quantitatively characterized in terms of contact angle, mass flow rate, and liquid absorption speed. The applicability of PDMS-based F-gates to the selective separation of oil and water even from oil-in-water emulsion was demonstrated by fabricating Janus PDMS-based F-gates. Our physicochemical volumetric modifications were also extensively analyzed to examine whether they satisfy the technological, economic, and ecological requirements of appropriate technology. This is the first effort to tailor the wetting properties of PDMS through physicochemical volumetric modifications, thus configuring a set of PDMS-based F-gates that act both as a separator for liquids of different STs and as a switch for fluid flows.

Facile Preparation of Raspberry-Like SiO2@Polyurea Microspheres with Tunable Wettability and Their Application for Oil-Water Separation.

Raspberry-like microspheres have been widely used as superhydrophobic materials, photonic crystals, drug carriers, etc. Nevertheless, their preparation methods, usually consisting of multiple steps, are generally time- and energy-consuming. Herein raspberry-like SiO2@polyurea microspheres (SiO2@PUM) are readily prepared via a one-step precipitation polymerization of isophorone diisocyanate in a H2O/acetone mixture with the presence of SiO2 particles. The sphere size, surface roughness, and SiO2 content of SiO2@PUM are easily adjustable by varying the experimental conditions. TEM and SEM observations reveal that the final SiO2@PUM exhibits a core-shell structure, with polyurea (PU) in the core and SiO2 particles as the shell. In the process, the SiO2 particles were initially located on the PUM surface as a monolayer. With the reaction proceeding, the monolayer of SiO2 particles became thicker, forming a thicker layer of SiO2 particles on PUM due to the accumulation of SiO2 particles, leading to a multilayer structure of SiO2 particles on the shell of SiO2@PUM. The formation mechanism of the raspberry-like SiO2@PUM was thoroughly discussed and ascribed to electrostatic attraction between the positively charged PU and negatively charged SiO2 particles. Once dried, SiO2@PUM was superhydrophobic and turned hydrophilic if water-wetted. Using a layer of SiO2@PUM, effective separation with good reusability for a variety of oil-water mixtures was achieved regardless of the oil density and types of oil-water emulsions. This work presents a novel protocol for the preparation of raspberry-like microspheres with tunable wettability via a rapid and green process, and the resulting microspheres are highly effective for the separation of diverse types of oil-water mixtures.

Wettability regulation of the electric double-layer structural evolution of complex fluids: Insights into thermodynamic and electrical properties

Understanding the structural evolution at the electrode is essential for accurate prediction of complex fluid applications, where the carbon nanotube is chosen as the carrier of CO2-ionic liquids (ILs) in electroreduction. Then, the electrical double layer with tunable wettability is investigated by molecular dynamics simulations. The competition and cooperation between van der Waals and Coulomb interactions are evaluated by examining the structural and electric characteristics. When an external potential (φ) is initiated, the co-ions are repelled from the electrode and the counter-ions compete with CO2 in the electric double layer (EDL), with different thermodynamics produced by varying the proportion of CO2/ionic liquid. As the solid–liquid interaction parameter (β) increases, more counter-ions aggregate, producing double density peaks for Tf2N− and sharply increasing the density of CO2. With increases in β and φ, the local charge density and local field potential increase, and the EDL thickness decreases. However, the location of the CO2 density layer shifts ahead to the counter-ions, weakening their shielding effect and capacitance. Using a combination of structural analysis, the first and second peaks of Tf2N− of EDL are composed of sulfonyl and trifluoromethyl, respectively. As a response, the steric hindrance of CO2 decreases, and more molecules migrate to the surface in a parallel orientation. The structural evolution is quantitatively evaluated in terms of the entropy, results show that the orientation transition is prominent in structural evolution. The coupling relation between thermodynamic and electrical properties plays a pivotal role in determining the structural evolution of complex mixtures, and these findings could benefit the advancement of ILs-based CO2 electroreduction and other complex fluid applications.

Fumed silica additives enables tunable wettability of the resin for improved composite bipolar plate

Composite bipolar plates (CBP) composed of resin and conductive filler are critical components in proton exchange membrane fuel cell (PEMFC) for achieving mechanical strength and electrical conductivity. The conductive filler entirely enveloped by resin is of significance for the flexibility of the CBP; while connected resin blocks the continued conductive channels and thus weakens the electrical properties of CBP. Herein, we propose a trade-off method between flexibility and conductivity of the CBP by wettability regulations of the resin, in which fumed silica additives are introduced into epoxy as composite adhesives. The abundant hydrogen bonds are demonstrated to be well-formed between epoxy and fumed silica for decreasing surface free energy (SFE) between resin and graphite. As a result, the composite adhesive with 2 % fumed silica delivers moderate wettability enabling much improved CBP, which exhibits high electrical conductivity of 233.33 S cm−1 as well as flexural strength of 66.4 MPa. Moreover, the CBP also delivers improved areal specific resistance (5.34 mΩ cm2), thermal conductivity (10.58 W (m K)−1), and corrosion behaviors (0.0701 A cm−2) which guarantee the operation of the PEMFC. This work provides new insight from the wettability regulation of resins for improved CBP, which is an easy-operating method and has great potential for application in practical CBP fabrication.

Bioinspired Hierarchical T Structures for Tunable Wettability and Droplet Manipulation by Facile and Scalable Nanoimprinting.

Developing surfaces that effectively repel low-surface-tension liquids with tunable adhesive properties remains a pivotal challenge. Micronano hierarchical re-entrant structures emerge as a promising solution, offering a robust structural defense against liquid penetration, minimizing area fraction, and creating narrow gaps that generate substantial upward Laplace pressure. However, the absence of an efficient, scalable, and tunable construction method has impeded their widespread applications. Here, drawing inspiration from springtail epidermal structures, octopus suckers, and rose petals, we present a scalable manufacturing strategy for artificial micronano hierarchical T-shaped structures. This strategy employs double-transfer UV-curing nanoimprint lithography to form nanostructures on microstructured surfaces, offering high structural tunability. This approach enables precise control over topography, feature size, and arrangement of nano- and microscale sections, resulting in superamphiphobic surfaces that exhibit high contact angles (>150°) and tunable adhesive forces for low-surface-energy liquids. These surfaces can be applied to droplet-based microreactors, programmable droplet-transfer systems, and self-cleaning surfaces suitable for various liquids, particularly those with low surface tension. Remarkably, we have also succeeded in fabricating the hierarchical structures on flexible and transparent substrates. We demonstrate the advantages of this strategy in the fabrication of hierarchical micronanostructures, opening up a wide range of potential applications.

Tunable Wettability of a Dual-Faced Covalent Organic Framework Membrane for Enhanced Water Filtration.

Membrane technology plays a central role in advancing separation processes, particularly in water treatment. Covalent organic frameworks (COFs) have transformative potential in this field due to their adjustable structures and robustness. However, conventional COF membrane synthesis methods are often associated with challenges, such as time-consuming processes and limited control over surface properties. Our study demonstrates a rapid, microwave-assisted method to synthesize self-standing COF membranes within minutes. This approach allows control over the wettability of the surface and achieves superhydrophilic and near-hydrophobic properties. A thorough characterization of the membrane allows a detailed analysis of the membrane properties and the difference in wettability between its two faces. Microwave activation accelerates the self-assembly of the COF nanosheets, whereby the thickness of the membrane can be controlled by adjusting the time of the reaction. The superhydrophilic vapor side of the membrane results from -NH2 reactions with acetic acid, while the nearly hydrophobic dioxane side has terminal aldehyde groups. Leveraging the superhydrophilic face, water filtration at high water flux, complete oil removal, increased rejection with anionic dye size, and resistance to organic fouling were achieved. The TTA-DFP-COF membrane opens new avenues for research to address the urgent need for water purification, distinguished by its synthesis speed, simplicity, and superior separation capabilities.

Additive manufacturing of heterogeneous combinatorial functional surface by plasmonic hierarchical sintering of silicon particles for active manipulation of rheological liquid motion

We present a sustainable and efficient additive manufacturing method of silicon-based heterogeneous combinatorial functional surfaces designed to actively manipulate liquid droplet motion dynamics to address advanced rheological engineering challenges and applications. This additive manufacturing enables the instantaneous formation and control of hierarchical multiscale structures with tunable wettability through instantaneous plasmonic thermophysical sintering between laser and Si particles, eliminating the need for additional masks and subsequent processing steps. Furthermore, this fabrication approach can selectively implement heterogeneous combinatorial functional surfaces in a single domain by reversibly switching extreme wettability modes (e.g., from superhydrophobic to superhydrophilic) upon laser irradiation. Continuous superhydrophilic channels in a superhydrophobic background created by selective laser re-irradiation provide sufficient local attraction to manipulate droplet motion along the channel due to van der Waals forces and Laplace pressure fields generated by the difference in wettability. Active manipulation of droplet dynamic motion, such as trajectory tracking and antigravity self-propulsion, can be realized by simply designing a laser scanning path that determines the geometry of the local channel. The manipulation platform for liquid motion dynamics can be applied to active microfluidic channels with no cavity, without the need for an external power source. This advancement has important implications for broad fluid and rheological engineering applications.

Wettability tuning on stainless steel LIPSS by laser oxidation and its implication on cavitation bubble dynamics

The modification of surface wettability of stainless steel is essential for many biological applications and industrial implementations. Having a hydrophobic or hydrophilic surface is ideal depending on its application. In this study, the wettability tuning of stainless steel was carried out by producing LIPSS at different laser peak energies. Results showed non-significant changes in the periodicity of the ripples, however hydrophilicity increased with greater laser energies. Raman spectroscopy and SED analysis demonstrated the presence of iron oxide peaks and increased oxygen concentration, demonstrating a chemical surface modification governed by oxidation. Transitions from hydrophilic to hydrophobic surfaces were accomplished by ethanolic triethoxyoctylsilane coated LIPSS. Hydrophobicity enhancement was achieved by the adsorption of organic species promoted by the oxide layer at the ripples. The dynamics of cavitation bubbles close to the coated LIPPS were analyzed. A reduction of the main bubble lifetime with hydrophobicity, whereas a delay of collapse time and deformation of the rebound bubble were found. This led to an experiment for erosion testing producing multiple cavitation events. An increment of surface damage area with increased hydrophobicity was observed. This was attributed to longer collapse times of the rebound bubble which led to stronger shockwaves at the samples surface. This work demonstrates a simple method to tune the surface wettability of stainless steel by laser oxidation, which is a crucial factor for applications related to cavitation phenomena.

Smart wetting based on thermal-induced dual-scale surfaces

Surfaces wettability influences drag reduction in engineering applications, and surface structure largely determines the wetting properties. This study proposes a novel thermal shape memory polymer (TSMP) with dual-scale structure surface capable of reversible transformation via working temperature. A preparation method for TSMP with micro-nano dual-scale structure is also proposed to enhance hydrophobicity comparing with microstructure. Experimental results indicate TSMP micro-nanostructure surfaces achieve reversible conversion between hydrophilicity and hydrophobicity, TSMPs with micro-nano structure also exhibit good recovery. Simulation was established to understand tunable wettability and fluid flow mechanisms of TSMP reversible two-phase microstructures aiding design of TSMP microstructures with adjustable wettability.

Fabrication of natural microcapsule with intrinsic core–shell structure as building blocks for achieving source control of obesity

Regulating oil absorption at the intestinal absorption site is a safe and effective strategy for controlling obesity. Nevertheless, all patients may experience adverse effects from medication, including lipase inhibitors. Herein, we report the preparation of natural core–shell sporopollenin microcapsules with the ultimate goal of solidifying lipids post-lipase inhibition, thus exploring a safe and effective strategy for controlling lipid absorption in obesity. Naturally occurring micro/nanoparticles provide an incredible array of potential sources for fabricating pharmaceutical microcapsule carriers. Natural pine pollen was treated with phosphoric acid to yield intact, clean, and monodisperse microcapsules. Their intrinsic core–shell structures can be harnessed as potential carriers for pharmaceutical microcapsules, ensuring their viability for large-scale production. This study proposes an innovative strategy for complementary source control of obesity utilizing natural core–shell sporopollenin microcapsules and lipase inhibitors. Natural pine pollen microcapsule carriers exhibit natural core–shell structures, tunable wetting properties, and excellent liquid absorption capabilities. Interestingly, as-prepared hydrophobic pine pollen microcapsules can be utilized for the solidification of liquid drugs. Moreover, their strong oil adsorption capability can solidify lipids in complex oil–water systems post-oral lipase inhibition. Derived from pine pollen, these natural microcapsule carriers can be produced on a large scale and boast the safety of being food-derived, making them promising candidates for essential components in obesity source control.

Tuning the wettability of alginate-based nanocomposite beads for efficient removal of pharmaceuticals from water

Long-term exposure to pharmaceuticals, such as diclofenac (DCF) and tetracycline (TC), poses various risks to human health, including antibiotic resistance and endocrine disruption. In this work, we investigated the removal of DCF and TC from water and probed the removal performance of contaminants in a complex matrix consisting of DCF and TC mixtures using alginate (AL)-based nanocomposite beads with tunable wettability. We improved the selectivity of the beads towards hydrophobic contaminants by reducing graphene oxide (GO) to rGO in the presence of AL using a mild and green reducing agent (Vitamin C). Thein-situchemical reduction of GO in AL matrix resulted in amphiphilic rGO-containing beads,as confirmed by several characterization techniques.Thein-situreduction, apart from restoring the sp2hybridized carbon, greatly improved the mechanical properties and stability of the nanocomposite, ensuring reusability beyond 10 adsorption/desorption cycles.Compared to neat AL beads, the addition of only 3.5% rGO (AL:3.5rGO) improved the beads adsorption capacity for TC and DCF by 660% and 747%, respectively. The beads exhibited remarkable performance in the simultaneous removal of TC and DCF from contaminant mixtures. The superior performance of AL:3.5rGO beads is attributed to the enhanced π-π interactions between the aromatic rings of the contaminants and the sp2domains of rGO-containing adsorbents.

Enhanced wettability of gallium-based liquid metal alloys on copper films by promoting intermetallic reactions

Gallium-based liquid metal alloys (LMs) have promising prospects as circuit components for flexible electronics, while, their high surface tension is now challenging for wetting of LMs on polymer surfaces and further patterning. In this study, we prepared functional Cu thin films on PDMS to enhance wettability of EGaIn liquid metal, using metal reaction-enhanced wetting. By adjusting the deposition pressure for Cu film deposition and introducing silicon-bound PDMS, both surface characteristics and microstructures of the Cu films change greatly. The corresponding contact angle of EGaIn can be tuned from 19° to 79.5°. The folded texture of the Cu film surface reduces the actual contact area, leading to an increase in the contact angle. The higher I(111)/I(200) ratio in the Cu films improves the surface wettability, probably due to the fact that the (111)-phase orientation promotes the formation of CuGa2 reaction products. This tunable wettability of LMs is expected to improve the performance of flexible electronic devices.

Engineering Tough Supramolecular Hydrogels with Structured Micropillars for Tunable Wetting and Adhesion Properties.

Soft-lithography is widely used to fabricate microstructured surfaces on plastics and elastomers for designable physical properties such as wetting and adhesions. However, it remains a big challenge to construct high-aspect-ratio microstructures on the surface of hydrogels due to the difficulty in demolding from the gel with low strength and stiffness. Demonstrated here is the engineering of tough hydrogels by soft-lithography to form well-defined micropillars. The mechanical properties of poly(acrylamide-co-methacrylic acid) hydrogels with dense hydrogen-bond associations severely depend on temperature, with Young's modulus increasing from 8.1MPa at 15°C to 821.8MPa at -30°C, enabling easy demolding at low temperatures. Arrays of micropillars are maintained on the surface of the gel, and can be used at room temperature when the gel restores soft and stretchable. The hydrogel also exhibits good shape-memory property, favoring tailoring the morphology with a switchable tilt angle of micropillars. Consequently, the hydrogel shows tunable wetting and adhesion properties, as manifested by varying contact angles and adhesion strengths. These surface properties can also be tuned by geometry and arrangement of micropillars. This facile strategy by harnessing tunable viscoelasticity of supramolecular hydrogels should be applicable to other soft materials, and broaden their applications in biomedical and engineering fields.

Droplet Morphology-Based Wettability Tuning and Design of Fog Harvesting Mesh to Minimize Mesh-Clogging.

Fog harvesting relies on intercepting atmospheric or industrial fog by placing a porous obstacle, for example, a mesh and collecting the deposited water. In the face of global water scarcity, such fog harvesting has emerged as a viable alternative source of potable water. Typical fog harvesting meshes suffer from poor collection efficiency due to aerodynamic bypassing of the oncoming fog stream and poor collection of the deposited water from the mesh. One pestering challenge in this context is the frequent clogging up of mesh pores by the deposited fog water, which not only yields low drainage efficiency but also generates high aerodynamic resistance to the oncoming fog stream, thereby negatively impacting the fog collection efficiency. Minimizing the clogging is possible by rendering the mesh fibers superhydrophobic, but that entails other detrimental effects like premature dripping and flow-induced re-entrainment of water droplets into the fog stream from the mesh fiber. Herein, we improvise on traditional interweaved metal mesh designs by defining critical parameters, viz., mesh pitch, shade coefficient, and fiber wettability, and deducing their optimal values from numerically and experimentally observed morphology of collected fog water droplets under various operating scenarios. We extend our investigations over a varying range of mesh-wettability, including superhydrophilic and hydrophobic fibers, and go on to find optimal shade coefficients which would theoretically render clog-proof fog harvesting meshes. The aerodynamic, deposition, and overall collection efficiencies are characterized. Hydrophobic meshes with square pores, having fiber diameters smaller than the capillary length scale of water, and an optimal shade coefficient are found to be the most effective design of such clog-proof meshes.

Bioinspired thermo-responsive membrane with hybrid micro/nanostructure for water gating and emulsion separation

Smart membranes with tunable wettability hold great promise for controllably oil/water mixtures separations, including oil-water mixtures and surfactant stability oil/water emulsions. Herein, a thermo-responsive membrane with bioinspired hybrid micro/nanostructure was constructed on commercial PVDF membrane, which exhibits excellent thermo-responsive performance and antifouling ability. In this process, the thermo-responsive polymer graft to membrane surface via thiol-ene click reaction, preserve the high interfacial roughness and excellent switching wettability between hydrophilicity/underwater oleophobicity at 25 °C and hydrophobicity at 50 °C. The membrane can be applied in various surfactant stability oil-in-water emulsions and water-in-oil emulsions, demonstrating high separation efficiency, recyclability for various kinds of emulsions. The hybrid micro/nanostructures render the membrane with excellent antifouling performance. The membranes show good potentials for smart liquid separation such as on-demand oil-spill cleanup, remote controllable operation of oil/water emulsion separation device.

Boric acid-regulated gelation and ethanol-assisted preparation of polybenzoxazine aerogels

Polybenzoxazine aerogels have gained widespread attention in recent years, but the prevalent use of hazardous solvents in the preparation process has severely impeded their further development and promotion for practical applications. Herein, using ethanol as a solvent, a strategy of boric acid-induced microstructure regulation is proposed to construct boron-doped polybenzoxazine (BPBz) aerogels, which provides a feasible approach to overcome the above situation. The introduction of boric acid enhances the backbone strength by forming intermolecular bridged structures between PBz chains and allows the use of ambient pressure drying. The resulting BPBz aerogel demonstrates high stiffness (specific modulus up to 255.97 kN·m·kg−1), low bulk density (0.203 g·cm−3), and low thermal conductivity (0.043 W·m−1·K−1), exhibiting excellent fire resistance when exposed to a 1200 °C flame (the self-extinguishing interval less than 1 s). More interestingly, the aerogel demonstrates intrinsic and tunable wettability that correlates with the morphology. Combining the environmentally friendly preparation strategy and these advantages, BPBz aerogels hold promise for thermal management and fire protection applications in energy-saving construction and other harsh conditions.

Tunable Surface Wettability via Terahertz Electrowave Controlled Vicinal Subnanoscale Water Layer.

Achieving timely, reversible, and long-range remote tunability over surface wettability is highly demanded across diverse fields, including nanofluidic systems, drug delivery, and heterogeneous catalysis. Herein, using molecular dynamic simulations, we show, for the first time, a theoretical design of electrowetting to achieve remotely controllable surface wettability via using a terahertz wave. The key idea driving the design is the unique terahertz collective vibration identified in the vicinal subnanoscale water layer, which is absent in bulk water, enabling efficient energy transfer from the terahertz wave to the rotational motion of the vicinal subnanoscale water layer. Consequently, a frequency-specific alternating terahertz electric field near the critical strength can significantly affect the local hydrogen-bonding network of the contact water layer on the solid surface, thereby achieving tunable surface wettability.

Construction of chitosan-gelatin polysaccharide-protein composite hydrogel via mechanical stretching and its biocompatibility in vivo

Natural polysaccharides and protein macromolecules are the important components of extracellular matrix (ECM), but individual component generally exhibits weak mechanical property, limited biological function or strong immunogenicity in tissue engineering. Herein, gelatin (Gel) was deposited to the stretched (65 %) chitosan (CS) hydrogel substrates to fabricate the polysaccharide-protein CS-Gel-65 % composite hydrogels to mimic the natural component of ECM and improve the above deficiencies. CS hydrogel substrates under different stretching deformations exhibited tunable morphology, chemical property and wettability, having a vital influence on the secondary structures of deposited fibrous Gel protein, namely appearing with the decreased β-sheet content in stretched CS hydrogel. Gel also produced a more homogenous distribution on the stretched CS hydrogel substrate due to the unfolding of Gel and increased interactions between Gel and CS than on the unstretched substrate. Moreover, the polysaccharide-protein composite hydrogel possessed enhanced mechanical property and oriented structure via stretching-drying method. Besides, in vivo subcutaneous implantation indicated that the CS-Gel-65 % composite hydrogel showed lower immunogenicity, thinner fibrous capsule, better angiogenesis effect and increased M2/M1 of macrophage phenotype. Polysaccharide-protein CS-Gel-65 % composite hydrogel offers a novel material as a tissue engineering scaffold, which could promote angiogenesis and build a good immune microenvironment for the damaged tissue repair.

Controlled Preparation of Highly Stretchable, Crack-Free Wrinkled Surfaces with Tunable Wetting and Optical Properties.

Constructing wrinkles by utilizing strain-driven surface instability in film-substrate systems is a general method to prepare micronano structures, which have a wide range of applications in smart surfaces and devices such as flexible electronics, reversible wetting, friction, and optics. However, cracks generated during the preparation and use process significantly affect the uniformity of wrinkled surfaces and degrade the functional properties of the film devices. The realization of crack-free wrinkles with high stretchability in hard film systems is still a great challenge. Here, we report on a facile technique for controllable preparation of large-area, highly stretchable, crack-free wrinkled surfaces by ultraviolet ozone (UVO) treatment of Ecoflex. The thickness dependence of the wrinkles and the in situ wrinkling process during mechanical loading are investigated. The wrinkles including striped, labyrinth-like, herringbone, and transitional structures are controllable by changing strain mode (uniaxial or biaxial), loading history (simultaneous or sequential), strain anisotropy, and gradient loading. The wrinkled surfaces obtained using UVO-treated Ecoflex have tunable wetting and optical properties and can maintain excellent mechanical stability under large strains. This study provides a facile method for the preparation of large-area, crack-free wrinkles, which is simple, fast, low-cost, and robust. The resulting wrinkled surfaces remain stable under high stretching, which is beneficial for many practical applications, especially in the cases of large strains.